On one hand, it's an etiquette thing to content warn on posts of obscene or vulgar matter. same goes for including tags that are specific enough to be parsed. However, individual sensibilities vary wildly, and it's impossible to cater to everyone.
On the other hand, Mastodon/ActivityPub is stuck in that twitteresque culture, and never matured beyond that.
Now, at least with #Nostr and it's relay system, clients can choose to exclusively use restrictive relays like what's capable with #ditto to tailor their feed as they see fit, or include less restrictive relays when they choose.
I tailor my relay to remove a lot of detestable events, but in my own clients use more than just one relay.