I don't like the mob thing either but it's how large group dynamics on the internet work (by default). We try to mitigate it where we can but there's not a lot of knowledge about how to do that.
And either ban "this is offensive" comments or politics altogether.
Re politics: it's not possible to ban that altogether, nor would it fit HN's mandate of intellectual curiosity to do so. For past explanations see https://hn.algolia.com/?dateRange=all&page=0&prefix=false&so.... If there are questions I haven't answered there, I'd be happy to answer them.