I really hope people at least understand that when Oda wrote that scene, he had zero to no intentions of portraying rape or anything of that severity.
Was he misinformed? Yes, was it something that he should looked into? Yes probably.
It was a honest mistake, he's not omnipotent and this can be said for this case with the mess that is Yamato's gender too.
His intention then with Sanji, was to portray it as a comedy-ish scene and it is very difficult for him to flesh out the okama in the limited panels, so the way he went about it was to have them act in the one-way that in his mind that he is most familiar with. This familiarity is a problem and is a underrepresentation, and even a poor one of the community but I don't necessarily think he did it with an intention of generalizing them.
Transgender issues in Japan hasn't been the most progressive WHEN compared to the States but it has been improving and if you've spend enough time with Japanese media, there are way way more shows/manga/whatever that overly generalize transgender people as a certain type of mama personality. You would, however, find this stereotype in early American movies too which surprisingly is something that the older generation of Japanese would easily stereotype or generalize when they think about transgender personalities.
Which is wrong because the world is more progressive now but I don't go full fire on Oda if that's his first thought to fall back on when it comes to writing characters of that nature because I at least understand that this is not what his work is about and he has never had the intention to degrade them. I like to believe he wants to be more progressive but can be prone to mistakes, but the intention of wanting to shouldn't be a mistake we focus on. This guy wrote amazing transgender characters (mr 2) that relatively speaking was not seen in the industry for decades and has not yet been topped. The west needs to understand that being sensitive and "correct" about the minority communities is not something that is as much in-your-face or an open conversation as it is in countries like Japan. Unlike the culture over there, Oda isn't frequently in contact with this sensitivities or the insensitivities that should be practiced. It doesn't mean that he shouldn't put more effort into researching and understanding but give the guy a break and practice some cultural understanding.
If I'm not wrong and this is obviously going to piss people off, I think his intentions for Yamato has been to have a different kind of female character to join the crew that stands out from Robin and Nami while being very strong and is, like many straw hats, influence by a major character(which is Oden). He obviously didn't want to write another guy, which is how Yamato comes into play. This is 100% conjecture and time will tell whether I am right. He don't want to write another male straw hat, the crew is lacking of females but he still want someone to carry oden's legacy to be one the boat. Another female that is not physically combat fit will be very similar to Nami and that's a problem.
Once again, conjecture so don't flame me but if you do, sure I'll get it. I won't even be surprised if I come back to this thread a year from now and Yamato is dressed in female attires in color spreads because the production crew from writing to the anime has made little attempts to portray her otherwise.