>>42693410Sylveon looks like the trans flag and people ran with that. Plus it's a FAIRY. Not known for being masculine.
Same thing in reverse with female Fighting Types. There's a gender norms thing goin' on here.
You'll notice however that for the most part nobody has problems with girls being tough. Our society doesn't really mind butch girls that much but they HATE fags and this is reflected by the fact that so many people hate Fairy Types and raise an eyebrow whenever a Fairy Type is male.