Buggy is the leader of Cross Guild a group of people that put bounties on the marines. Since the marines think that Crocodile and Mihawk are Buggy's subordinates they gave him a high bounty.

I mean Roger and Garp were kinda haki gods

Buggy leads an organization that hunts Marines and already caused the death of a recently promoted Vice Admiral (T Bone).

He also has under his command 2 former Shichibukai, one who is the world's strongest Swordsman and the other almost destroyed a WG affiliated Country (Alabasta).

And to top it off, he has territory AND was a member of the Pirate King's crew.

It wasn’t JUST Roger and Garp, Roger had a crew, the holy knights were also there, and the Gorosei too but I really doubt they fought

I know WHY he has the bounty it's just wierd to see his bounty being higher than Luffy solely because people think he practically owns Mohawk and alligator, and is the past crewmember of Roger. In reality he beat a vice admiral level swordsman, with a devil fruit specifically against regular swords. I know your role in the navy isn't exactly your power and danger level like bounties (proven by Garp), but still I never really saw T bone as a powerful navy soldier.

AlligatorMom

Yes. Mohawk and alligator. Don't forget white moustache and da Mingo and we can't possibly forget Giant mother

Captain: Fluffy

First Mate: Losto Mossbrain

Cook: Dr. Curlybrows

Helmsman: The wiiiiiiide blue…

Buggy is one of the former crewmates of the recent pirate king it boosted his reputation

Mihawk has a higher bounty than Luffy. In the eyes of the WG, Buggy is Mihawk's Captain, so they could assume buggy is stronger/more dangerous

Bro what ?!

Buggy is now allied with Mihawk and Croco, and he is puttin bounties on the Mariners 😂

But sure, Oda is not consistent with bounties for a long time