Here’s the beginning of the Wikipedia article:

Kiwi Farms, formerly known as CWCki Forums, is a web forum that facilitates the discussion and harassment of online figures and communities. Their targets are often subject to organized group trolling and stalking, as well as doxxing and real-life harassment.

So, it’s an assholefarm.

Although the name originated with one particular site, it looks like the name now applies to any site that serves a similar purpose. Bleah.