the only way for an average user to get exposed to such rooms
But there is a growing dissent for matrix.org itself as a homeserver for various reasons, and many people/blogs/posts/etc. online will try to steer users towards alternative "privacy-respecting" or "free-speech/anti-censorship" (aka allowing illegal content) servers, many of which of course host terrible content, so I think more and more people are getting exposed to it and realizing how bad of a problem it is.