The underlying problem is that browsers are not designed with this sort of federated application use case in mind, so Mastodon and friends have to do some awkward tricks to get it to work at all.
Normal people do not care enough to go on a safari hunt for finding instances, user names of those claiming to have left Twitter or deleting their accounts or even bothering self-hosting just for a username on their own instance.
I know many people used Twitter.com or their official app, but many people find a simpler native app experience much more useful.
It's frustrating that the web platform doesn't accommodate federated services like Mastodon that span multiple servers very well, but those are the cards we're dealt. It does work, it's just not ideal.