Here's an analysis of Braco, and how he relates to the culture of Ooo:
For those who haven't seen The Suitor, Braco is basically a suitor, who intended to carry on the family tradition of attempting to marry Princess Bubblegum after his father passed away.
Now, I view Braco's obsession with Princess Bubblegum as kind of an indicator of some kind of misogyny that once existed in Ooo, but went away somehow. Now, let me explain why Braco's love for Peebles is misogynistic.
Now, I could say that Braco certainly has a sense of entitlement and an inability to move on, but I wouldn't say that makes him full-on sexist. What makes him misogynistic is that he doesn't actually love Princess Bubblegum. He wants to marry her not because he loves her or is attracted to her in any way, but because he wants to please his father. So basically, PB is just the object in which Braco intends to live up to his father with. So basically, he doesn't have any attraction to her at all, and treats her and sees her as nothing more than a means to an end
Now, Braco learned this from his father, who was from a previous generation. The only other misogynist character we've seen is Ash. Now, considering that Ash has been in a relationship with Marceline for a while, we can assume that he's somewhat old, and given his magical powers and the fact that he was in a relationship with an immortal, also immortal himself. So basically, he came from a previous generation just as Braco's father did.
And, in one of the Adventure Time comics, Marceline snapped at Finn for saying that he didn't expect her to be good at computers, because she assumed that he was being sexist. Marceline is also immortal, and therefore also existed in a previous generation. Her reaction implied that she had heard plenty of sexist patronizing in the past. Now, this could have come from Ash, but where did Ash learn it from?
My theory is that there was a deeply misogynistic culture in Ooo, that existed after the Great Mushroom War but before Finn was born. The only sexist characters all probably existed in a previous generation, before the birth of Finn, and the only one who existed after learned it from his father.
Now, I doubt this sexism exists after Finn's birth due to the fact that nobody born after Finn is sexist, and that a majority of Ooo's rulers are in fact female by time Finn was born. So, something must have happened before Finn was born that cased a vast majority of this sexism to dissolve. Did one female ruler rise up, inspiring others to do the same? Did all of the sexists merely die off without spreading their beliefs, with only a few exceptions? Did Princess Bubblegum make some kind of feminism raygun? I don't know.
But I do have an idea to how this culture of objectification started. During the GMW, the human population would have dwindled immensely. During Finn the Human, it was shown that civilization had regressed, and very few people were left.
I think that women were basically treated as baby factories, because the human species was dying out and needed to produce as many new children as possible. This idea of women only existing for reproductive purposes stayed with those who survived the Great Mushroom War by mutation or other means, who spread it to their children and so on until whatever caused it to die out caused it to die out.