i dont remember which but some lemmy apps have word filters for posts so it could be very practical for you.
I think liftoff was one of them but i am not really sure
I know that posts like this annoy people like you that are fed up but some of us others like every piece of humilation that our ex has and realistically we wont stop to post some news from time to time so to block the content looks like a good option to me
Edit: I had a closer check and I don't think the Lemmy protocol itself currently allows you as a user to block an entire instance? Someone smarter than me please correct me if I'm wrong.
Except that the user they were responding to is on lemmy.ml and the reddit community is on lemmy.world. Correct me if I'm wrong, but this post wouldn't show up on for them unless they'd joined the community directly.