there's not a lot the law can do, unfortunately. doxxing isn't illegal in the US, at least federally, except against people in certain positions [0]. there's a high standard for harassment to be considered illegal. bullying is not illegal. hate speech is not illegal. even if individuals on Kiwi Farms can be prosecuted, it wouldn't take the site down. and to be prosecuted, the prosecutors would have to care. there just aren't the laws..
I'm friends with a few people who have been targeted by Kiwi Farms. Near is far from the only person driven to suicide by overwhelming bullying. it's one reason I keep a low profile - I'm just too scared.
> there's a high standard for harassment to be considered illegal
True, although it's sometimes possible to do a 2-step process under a lower standard. First, ask for a restraining order in civil court. Getting a restraining order has a much lower bar than charging someone with a crime does. If they don't stop, and violate the terms of the restraining order, then they can be sanctioned in various ways (civilly or criminally) for violating the restraining order, depending on the jurisdiction.
There are organizations that regularly do this pro bono for domestic violence cases, where the process is pretty well understood [1]. I'm not as sure what organizations or assistance exist for online harassment, unfortunately.