Current headcanon is Buggy was a slave before meeting Roger. BUT he was NOT like a coal-mining or house-servant slave. He was like, a victorian garden dwarf. A toy for the children and pet to do tricks at parties.
Roger takes him in and it never deeply clicks with Buggy that he’s “just the same” as Shanks. The *last* people who had buggy *also* had their own child and were *very* explicit Buggy was not ‘a child’ in the familial sense and was a source of entertainment not a person.
ooooooof..... OOF. Like, yeah, that fits to a T. Buggy coming to the Roger pirates with so much fucking baggage relating to being 'just a freak' (in part, no doubt, because of his facial difference!) who is to be owned and treated like entertainment for the real son of the household... And the Roger pirates absolutely NOT seeing him in that way, but also not really having Luffy-style therapy chops to dig into this and give Buggy the impetus to work through it. They really don't strike me as an emotionally aware bunch, alas...
And so, Buggy grows up still half-convinced he was only ever inducted into the crew for Shanks, whether as company or a source of amusement. No wonder his whole Performative Clown shtick became a bit of a reclaimed coping method that he has a weirdly fraught relationship with, as an adult!
