Please don't demand content warnings from strangers. Content warnings are a sort of social contract between an author and their followers; if you are not happy with how someone chooses to use them, do not follow that person or outright mute them, or mute words.
One of the most alienating experiences on Mastodon I've observed is when someone posts about something they're passionate about or is part of their identity and the first response is "please cw that" from a complete stranger.
Thanks