Here's a good post IMO that sums up the problem with his point even from his side of the fedi:
https://poly.cybre.city/notice/AVf9LG9gtKom8SG5mC

"I think Mastodon's approach of pretending the Fediverse is private and secure is the real problem here - it gave users the false impression that their posts are private, while they are not. It pretends to have privacy settings and tools, but they are barely effective. The truth is, Mastodon is misleading its users. ActivityPub is not private. It never been."

I wouldn't be shocked if GS had working search back in the day too and it's clear that working search is something you expect from a social media network; hence why Pleroma/Misskey has it. It's just Pleroma restricts abuse of searches by forcing logins as a setting.

Also the hashtag spam attacks are proof it's a false sense of security because trolls will search hashtags and flood them or target people on them.