Suing is way more expensive and way more hostile than simply airing your grievances in public. And why not? That's what public forums are for. "Do nothing" and "sue them" are not your only options; we are part of a society, not merely party to a legal system.

It’s difficult to prosecute online harassment, and “hate sites and photoshopped images” aren’t illegal. There’s a right to freedom of speech in the US.

Further the 'hate-' prefix in an accusation makes it one I immediately tune out.

It's just a manipulative word that lets you incite people while not actually revealing what was said.

Slander is illegal, and while not exactly the same thing, there is a lot of overlap.

Depending on the nature of the site, there also might be rules around unfair competition that might be implicated.

There is a very high bar for slander in the US, especially for public figures.