Damnatio memoriae is devastating to a public figure, but it is doing KiwiFarms a huge favor. It lets them scurry away under some new rock and keep going under a new name. The worst thing you could do is probably just shine the brightest spotlight you can find square at their activities.
There is a good reason we erect monuments and museums to atrocities. It's not for ease of rubbernecking, but so that we can learn and avoid them in the future.
Although it does enhance my point, which is that Kiwi Farms benefits from this.
If you try to convince them, likely you would get an unbelievable amount of negative online attention sent your way. Ironically the same thing they hate Kiwifarms for.