(I have taken a calculated epistemic risk in using these colours. They are based on the Red, Blue and Grey tribes identified by Slate Star Codex, but those tribe designations are cultural – they're defined by things like food preference and music preference, and are apolitical and morally neutral (in as much as anything is). They're also American and don't translate perfectly to a British context.
The groups I'm writing about here are political (in a broad sense, not just party political) and morally significant. They correlate with the cultural tribes, but not perfectly. It would be better for purity of discourse if I used random colours like orange, green and turquoise. But I think then people (including me - and, let's face it, I'm quite a big proportion of my readership) would lose track of which was which.)
Reds are people like Trump, Farage, most Leave voters, your stereotypical racist uncle, and the stereotypical white taxi driver. They are a majority numerically, so they do well in elections. They are motivated by prejudice and fear of the Other, and a feeling that LGBT people are icky. On the positive side, they are also motivated by strong family and community ties, and a respect for tradition and stability.
Blues are woke / social justice people. They are motivated by compassion and equity (and, on the negative side, sometimes by the desire to *look* compassionate and equitable or to prove that other people aren't). They are often not fussy about what means they use to help the oppressed and punish oppressors (and, sometimes, those who look like oppressors, and those who fail to denounce oppressors strongly enough). They are not a majority numerically, but they are extremely powerful in academia, the media and the corporate world (especially academia), which gives them influence disproportionate to their numbers.
Greys are motivated by intellectual curiosity and a desire for truth, and they care about long-term stable meta-principles that will work to uphold justice regardless of who's in power, rather than ones that are narrowly focused on the particular social problems of 2020. They do care about compassion and equity, but not at the cost of truth or meta-principles. More importantly, they care more about enacting compassion and equity via policies that are actually proven to help the oppressed than policies that sound like they will but might be counter-productive. On the negative side, they can be prone to intellectual superiority complexes or robotic detachment. They are the ones sincerely asking questions with (at least potentially) factual answers, like "Do affirmative action and compulsory diversity training actually help or harm racial minorities and women?" and "Does giving puberty blockers to gender-questioning children actually help or harm them overall?" They also care a lot about ideas standing or falling on their own merits, rather than because of who holds them, and they would prefer bad ideas to be openly discredited rather than forcibly suppressed. They are a small minority numerically and don't have very much power. They include people like Scott Alexander and Tim Farron... and, dare I say it, James Damore, although if you haven't read his memo as a primary source but have only read Blue-media misrepresentations of it then please pretend I didn't mention him.
(I would identify as Grey, in case that wasn't obvious. I am writing this post partly to explain to my Blue friends that I'm not Red, as they might otherwise be inclined to suspect; and partly just to get my mental model written down so that I can refer to it concisely and so that other people can have it in their mental toolbox even if they don't necessarily agree with it.)
Blues feel like they're a brave and beleaguered minority, surrounded and attacked by Reds - and they're right. Many Reds are verbally abusive to Blues, and some are physically violent.
Greys feel like they're a brave and beleaguered minority, surrounded and attacked by Blues - and they're right. Many Blues are verbally abusive to Greys, and some mobilise to destroy their livelihoods.
Blues are often literally unaware Greys exist, because Greys are such a small minority and most Blues may never, or never knowingly, encounter them.
Greys obviously know Reds exist, because Reds are so numerous; but Greys are in danger of occasionally forgetting Reds exist, because they almost never encounter them in real life, because Greys are a small enclave within Blue territory, so there's a buffer of Blues in between Greys and Reds.
So when Blues encounter Greys, they usually mistake them for Reds. Blues are used to the only resistance against them coming inward, from Reds, not outward, from Greys. They pattern-match the unfamiliar Grey rhetoric to the familiar and hated Red rhetoric, because both are negative about Blue-ness. They don't understand that Greys generally share their values, but disagree about the means to achieve those shared ends. So they come down heavily on Grey dissent, and call Greys things like "bigots" and "Nazi scum", and hound them out of their jobs.
And sometimes when Greys encounter Reds, they mistake them for fellow Greys, because they're so unused to encountering actual Reds (as opposed to second-hand Redness quoted angrily by Blues). They pattern-match the unfamiliar Red rhetoric to the familiar and positively-viewed Grey rhetoric, because both are negative about Blue-ness. They can find themselves nodding along to a Red article critiquing the damage done by Blue zealotry, until the article says something actually racist and jars them out of it.
(Some Blues *are* aware Greys exist, and say things to them like "You can't stay neutral - that's taking the side of the oppressor! It's only your privilege that gives you that option!" This is obviously a lot better than mistaking them for Reds, but I think it still misses the point. Greys are not neutral in the sense of "meh, you're both as bad as each other." If they are "neutral" it's in the sense of "hang on, we need to step back from today's specific conflicts and craft meta-principles that will guide society through tomorrow's conflicts as well without collapsing." If most people (through no fault of their own) aren't capable of that, and a few people have the "privilege" that means they can, then it's in everyone's interest to encourage them to do so, not to prevent them.)
Greys are usually closer to Blues than to Reds on a one-dimensional Red-Blue axis, but are more concerned with pulling in a direction that's orthogonal to that axis. To adapt the Political Compass mapping slightly, Blues are left and Reds are right (although, here, on a sociocultural axis of traditionalism versus progressivism, rather than the economic left/right of the Political Compass), and Greys are down (libertarian, in the Political Compass social sense of non-authoritarian, live and let live, not in the sense of worshipping the free market). Greys are probably left of centre on the progressive–traditional left–right axis, but they care more about the up–down axis, and want to pull both Reds and Blues further in a vertical direction. But if Reds and Blues only recognise the single horizontal axis, then they project the diagonal grey arrows onto the thin horizontal grey arrows, and see Greys as pulling towards their enemies (Blues and Reds respectively) and indistinct from them.