It's overworld content, it's not designed to be tackeled by literally everyone on the server + others from other servers.
People have asked about this before and every time it's the same result. Learn to accept the idea that you are toeing the line with how the developers actually want you to deal with the hunt marks.

If anything, people clogging up instances are a huge issue. Causing non-hunting normal players unable to get into places sometimes. I've missed some big fish due to hunt trains before.
And then there's the real griefing - people putting hunts away from their spawn location to reset their HP, nullifying the work others have put into it. GM's actually do punish for that, thankfully. It's just really annoying.

But time and time again there are folks that think that it's okay to pile literally every character into a zone and witch hunt those who dare pull when they are ready, but not before their grandma could make a new account to join in.