https://sh.itjust.works/post/54266084/23458044

https://sh.itjust.works/post/65057602

https://sh.itjust.works/post/60136891

https://sh.itjust.works/post/59651741

There's probably more, but this is what a quick search turned up

He’s radically anti-left, with a block list of leftist users and instances that is only dwarfed by Tesseract.

Codes in censorship features and tries to sneak them by people before getting called out and making them optional for other instances while acting like he’s such a great person for doing so.

And really random stuff such as coding memes and gifs to be hard to discover and sort lower, putting limits on how often people can vote, making the software harder for the people who contribute the most content to try and force them to be less active.

The lemmy devs have arguably much more problematic opinions, but they were also wise enough to keep their opinions in their instance, and out of the code itself.