I think that there's an element of validation and indoctrination that is a serious concern here. In addition to an overall significant lowering of the discourse around things by allowing garbage quality trolls and other horrible comments, and in addition to bullying, aggressive behavior, stalking, and other things that are broadly considered unpleasant, this kind of behavior breeds more of this behavior.
Consider someone growing up on the internet. The more they're exposed to this sort of content, the more it will be normalized in their mind. The more they're exposed to this sort of content, the more likely susceptible people are to be radicalized by it, and to grow into the same sort of troll. Hiding or suppressing low-quality content creates a herd immunity effect. It prevents a shift of the Overton Window to where "generally allowable discourse" suddenly includes timestamping the most "salacious" parts of a child's video, or telling people to actually kill themselves, or sharing their purely racist, hate-filled viewpoints.
While you may rather be exposed to it because you have the strength and capability to view it as a curiosity and a sociological study, the impressionable among us maybe deserve to not be bombarded with garbage, and we may have a moral duty to at least make some effort to minimize indoctrination and radicalization on these platforms.