Unless...
He’s a collector of autographed wanted posters!
He wants to make certain who to protect his daughter from!
He’s an artist and studies wanted posters to improve his technique!
He is into recycling!
He is protesting the practices of bounty hunters by stealing all those posters so they can’t check them!

...there’s plenty of reasons he might have them. But I will admit only one seems more obvious than the others...he’s a mailman delivering the posters around putting them up for the bounty hunters!

A mailman with a cowboy desperado aesthete! Which sounds kinda awesome saying it out loud!

To be fair, a Mailman riding up to your house on a horse to hand deliver your mail is a lot cooler then someone dropping it of with a Car.

Exactly!

Would be cooler if they were riding bears...

Collector of autographed wanted posters? That’s just silly. There’s NO way something like THAT would ever end up in One Piece!

Hello! Someone summoned me?

He IS the mailman
He's making his own, to take out his enemies
He's bluffing, it's an absurdly long shopping list!