Didn't the Dear Leader of mastodon.social curtail the search functionality of m.s.? You can't even search your own posts in your own Home TL there. So I wouldn't be surprised if the same restriuctions have been baked into the software every mastodon instance runs. Also, what you still can do on m.s. is search people but not posts. Seems like the Dear Leader wants to increase traffic by all means. But I stop here as I am getting too cynical...