Mastodon.social is one of the riskier places to be if you're concerned about defederation.

There's a very large segment of the mastodon population that thinks servers ad big as .social are very bad for the ecosystem. A lot of instances defederate them out of principle.

The argument is that .social is so big that it's not possible to moderate effectively. It also presents a very large and inviting place to launch attacks from. We frequently see waves of spam, abuse, and just bot accounts originating from .social.

A lot of severs are already defederated from .social for these reasons