Not defending Facebook but the framing that Meta, specifically, is a risk vector for people seeking abortion in ways that any other internet platform people use to communicate (including this one) wouldn't be is harmfully inaccurate.
Your mastodon instance admin is very nice, I'm sure, but are you _positive_ they're willing to go to jail for you by refusing a subpoena if you've disclosed info in DMs here that could be used against you?
Decentralization doesn't solve this - encryption does.