The first time I tried using the Vocaloid gender function I was so disappointed that there was no second time.
Personally, I use the GEN function like you draw other parameters (with wiggles and saw patterns) to either slightly lower or higher certain vowels if the Vocaloid sings it weirdly (ex: too high pitched and I want to lower it). I do not think drawing one straight line through the whole song works properly (unless it's a really low amount of adjustment by like 5ish). (That being said, I think there are some genderbent covers out there that sound surprisingly well tuned.)
Anyway...
I feel like some popular people in the vocal synth community (ex: famous UTAU voice providers, well-known cosplayers who dedicate themselves to mainly being one Cryptonloid, really good Vocaloid artists) really like to "abuse" their platform on Twitter. Like I get sharing your humble opinion here and there, but some of them just keep posting their opinion aggressively every couple hours and get mad when someone challenges them. Like, you won't shut up about X, so don't get surprised if someone wants to "fight back" after being repeatedly insulted. Especially when they have a black and white ultimatum like "People who do X are so stupid, if you don't agree, you are also stupid". And then they get known for being a jerk instead of the thing they are good at. Feeling really sick of it lately...