Why is lemmygrad in the banned instances

Scrolling through the linked instances and noticed Lemmygrad was banned? Is it their politics or are they just annoying or smth.

The lemmy.ml instance federates with lemmygrad.ml, the collection of Marxist communities. It blocks lemmygrad.com, which currently redirects to the forum of choice for President Donald J. Trump. The latter does not seem to be hosted using lemmy and I think could not be federated with in any case? But presumably this was once the domain of a similarly-minded lemmy instance.

Some instances other than lemmy.ml do block lemmygrad.ml. Besides being a place for Marxist communities, the instance is also home to some very radical and very hostile users. I haven't been around long enough to really know the situation for myself, but I have seen mentions of lemmygrad.ml communities engaging in brigading in the past.