content warnings aren't just for white people, though. they're for preparing folks for the content they're viewing before they view it. it's informed consent.(note: using second person for the sake of rhetoric, but I'm not specifically talking about you)
assuming that folks want content warnings because they want to shut out all content perpetuates the harmful idea that content warnings are purely for blocking content. they're not.
the reason why I want content warnings is because I want to engage with content without having it shoved into my face. simply telling me to block everyone who posts about it without a content warning is counter to that idea, because you're basically telling people to stop engaging with the information out there.
social media is fueled by outrage, and the idea that people can't stop the firehose of information headed their way. forcing people to leave platforms because they're fed up with you throwing heavy shit in their faces is directly counter to the fact that people are sharing this shit to inform and to show solidarity.
like, vent all you want without CWs to your followers, but if you plan for your post to be shareable, you owe it to your audience to preface it with a very small summary of what you're talking about, to give your audience the ability to engage in context.
you're not going to engage with the folks who don't want to see your content anyway. want to change a racist's mind? your untagged meme won't change that. all you're doing is forcing mentally ill folks to ignore everything about the situation instead of taking in stuff at their own pace.
and, there are loads of black folks who are hit harder by this deluge of content because they have to deal with loads of anti-black shit every day. experience dealing with stuff, and maybe even the numbness that follows, doesn't mean it's okay to shove something in someone's face.