Demonizing and making caricatures of people who aren't subdued to your taste is in fact a method of pushing your ideology into someone else.
But then it's not like you speak for Oda, just use him as a vessel for said ideology
I don't think Oda was ever particularly demonising anyone. When Oda wrote the okama thing into the story for the first time with Bon Clay, as ridiculous as he was it seemed pretty clear to me that he was more in line with that whole period of Japanese history where people sort of reclaimed the word and took it from being a slur to a point of pride....ish. Lol. Not all okama are even just your exaggerated drag queen caricature either (which isn't something unique to Oda, mind you. Take Newkama Land for instance, there are people of many different appearances there, some goofy, some conventionally attractive, and I kinda got the idea that was meant to be the point.
Throw in the fact that okama are generally portrayed as extremely loyal and empathetic individuals (even the over the top caricatures in the Okama Queendom thought they were helping Sanji, they just...uh.... misunderstood him. Lol. And they also clearly cared about him post TS, and put themselves at risk to help stop the Marines from pursuing him), and I never really got the "Oda is a transphobe/bigot" allegations. Ivankov specifically is extremely over the top in terms of personality (obviously he is visually based on Frank n Furter for gods sake 😅. Speaking of, RIP Tim Curry......), but is introduced as a miracle worker who has saved countless people. Not because he is some kind of superhero, but because he has a knack for getting people to the point where they are willing to stand up and help themselves. Which has been a thing with Ivankov since he was a kid. He did the same thing for Kuma on God Valley. When everyone else crumbled and gave up hope, he got them back on their feet and made them want to fight to live. The guy is a living beacon of hope and positivity, of living and taking pride in who you are no matter what the world says. So, yeah. I don't think Oda is trying to insult or criticise anyone with his portrayal of okama?