unfortunately it is not like email. they don't block for spam, they block for things they don't like. i don't know if it is a cultural problem, or an consequence of the fact that mastodon started in the mid-2010s vs email which is ancient
And that would be fine if everyone ran their own servers. For a new user looking to create an account on someone else's server, it means that which one you pick matters and you need to know the admin policy, which makes "shopping" more difficult.
If Mastodon ever takes off for real, I expect that professionally run servers will be pretty popular.
