HN is not unbiased, and not above censorship. Political things make it to the front page all the time, but this is the wrong kind of political thing. We're not supposed to talk about ----cides, at least, this ongoing one.
There's a large amount of people flagging that specific topic and viewpoint, it's a regular thing on HN, I'm not surprised at all.
Uncomfortable truths.
Literally the first comment I read was of the sentiment "Palestinians are all terrorists and deserve this" so it's not really a wonder why no one wants to read this style of conversation
Presumably for the same reason things related to e.g. American politics gets flagged: everyone knows where they stand on the topic, and there's no good discussion to be had about it here – just flame wars.
Literally anything related to this conflict gets flagged immediately.
The initial October attacks weren’t flagged. Violence in exactly one direction is flagged.