You can be on topic and only making calm, cited comments, but get shadowbanned for having sufficiently controversial views.

HN is like any other forum which censors certain views for being controversial.

Like stating that BLM is a Marxist organization — with a citation to their founders describing it as such.

HN relies on your belief that they only ban people “starting trouble” to remove certain topics from conversation, like how Marxist activists are using historic wrongs as a way to undermine society and for their own selfish enrichment.