Well, assuming we're still discussing the issue of whether removing a subset of user-generated content makes website owners publishers, then I think it's quite reasonable to ask whether your publisher would remain solely concerned with brevity and style if they received submissions incorporating the same range of opinions and ideas as social media.
The tendency of open internet discussion to inexorably tend towards talking about Nazis (and the Godwin corollary that when open internet discussion reaches Twitter-scale, it inevitably attracts participants wanting to defend the Nazis) was the point. Publishers don't have to deal with that bullshit, which is one of the reasons why publishing isn't remotely similar to forum moderation. If they did, they'd be a lot more censorious on the ideas and opinions side.
Sure, there are absolutely no neo-Nazis or kids cosplaying being neo-Nazis or else remotely analogous to neo-Nazism on social media. How silly of me to imagine that social media moderators were deciding if and how to deal with ideas and opinions more likely to be deemed hateful or objectionable by their customers and illegal by certain jurisdictions than the manuscripts your publisher solicits.
Do you think that’s what we’re discussing here? Fascinating.