I find it convenient and pretty cool that you can post to Lemmy from Mastodon by tagging the Lemmy community at the bottom of the Mastodon post.

I noticed a little over a month ago, this stopped working for me when I'd post from my fosstodon.org account and tag any community hosted on lemmy.world, and upon inspection, I see that Lemmy.world defederated from fosstodon.org

Threads.net isn't even defederated by lemmy.world, it's under the linked instances list, but fosstodon.org is blocked? What was the reasoning for that?