Sure, in isolation, you can dismiss that kind of language as hyperbole and let it pass. But we're talking about a pattern of rhetorical style and substance over several years that they have been warned about several times, but with no evidence of any intent to reform. HN is not intended for this style of discussion, and people who continue to engage it are driving away people who do want to use HN as intended.
Its a pattern of rhetorical style that isn't what a reasonable person would call dehumanising language. Their comments might not be something you think is acceptable for HN, but using that word to describe their comments is a real stretch and devalues the word