It's worth considering that:
A) The Jedi had been effectively extinct for a generation, so it's not like what they dressed like would be that ingrained in people's memory.
B) The Jedi's number is also frequently established as being really thin by the time of the prequels, so while they were prominent figures, it's not like there were a lot of them roaming the worlds to begin with.
C) Tatooine is on the fringe of civilization. Most of the people there probably either didn't know much about the Jedi or didn't care that they were supposed to be gone.
D) The party GTFO Tatooine almost immediately after Obi Wan whipped out his lightsaber in public, so it's not like we would have been in the position of seeing whether or not Obi Wan whipping his lightsaber out in public caused a public freakout.
Yeah, it's silly on the surface that Obi Wan just dresses like a Jedi the whole time in retrospect, but there's enough in universe explanations to where it's not really worth getting caught up over it.
On a related note, as bad as the prequels were, it's always worth remembering that RotJ did this