I was mostly exposed to Macki when he was on his reign of terror on the forums and on his spin-off forum, ohiirthar. I don't remember if I actually joined or not, but all I know is that it was terrible. Macki also created a bunch of trolls that were immediately banned (which is what got him featured in dsz!!). He's also an emoji on the Discord, so his legacy lives on.
I don't remember the antisemitism, but it doesn't surprise me. He fully committed to being awful and trying to make everyone legitimately angry / upset.