If you're going to post like this, you should supply links so readers can make up their own minds.

We don't moderate when HN commenters "go against hivemind consensus". We moderate when they break the site guidelines. If you didn't do that, it should be straightforward to link to where the mods got it so wrong.

I think what makes something like you describe become inflammatory isn't the surface level fact, after all you're just conveying information, but the underlying message you might have been trying to convey with that information which isn't necessarily as neutral.

If you said something like: "I think it's cool that despite Marxism in America being a niche line of political thought thanks to our history that a movement as large and successful as Black Lives Matter was informed by Marxist thought due to its early leaders. And it seems that time has made Americans more open to Marxist ideas now that it isn't connected to a global conflict."

I don't think that is inflammatory at all and very well meets the bar of intellectual curiosity HN looks for. But if you brought up this fact in the middle of a discussion of the moment then, whether you intended it as one or not, folks will likely read it as a dogwhistle since it became one in counterprotest circles.