In my experience, content warnings are usually a product of authorial judgement. For instance, I once wrote an article that discussed some people with extremely racist views. It occurred to me that some people might not want to read quotes containing vile, offensive comments about their race (or even someone else's). So I put a warning at the top so that such people wouldn't read the article if they didn't think they could handle it. No one forced me to do it. No one would have come for my head if I hadn't. As far as I can tell, this is the usual case: people put content warnings on their content for reasonable things when they think it's a good idea. I really don't see anything remotely resembling a problem, and I think people only really get upset about content warnings as a proxy for the greater culture war.
