I'm tired of joining random servers only to be banned shortly afterwards because the players there didn't expect or want random people from the lobby joining. And actually, making servers unlisted by default would benefit both aspiring server owners who want to gain players as well as friend groups who want to keep their server closed off from the public.
With this change, friends who just want to play survival together can do so without interruptions from the lobby potentially griefing or bringing chaos. And for aspiring server owners, this change means that they would have a better chance of getting players even if they're starting from ground zero. Say you have 15 pages of servers in your server browser. Since servers are sorted by the number of players, a friend group of 6 would easily make it to the top and get the problems mentioned above (griefing/chaos). Meanwhile, the server owner trying to get other players would probably fall to page 10 or something because there's only 1 player on that server. So both groups are actually worse off by not unlisting new servers by default.
The plausible argument against this whole thing is that it would make server initiation tougher for newcomers. But I think it's really not that hard to teach them an extra step when creating a server, especially when you already have players asking "How do I create a server?" in the lobbies. The extra step would be to not unlist their server if they want their server to be public, which shouldn't be too tough to do if a server owner is determined enough to get their server out there.
If you just make new servers unlisted by default, you don't even need to have a whitelist. Friend groups who want to play survival together can just share the minehut.gg ip with each other, so they don't have to bother with banning random players they don't want to see.