Aside from the fact that the Marines in general had a fairly disdainful attitude towards civilians, I don't really see it as "mocking" to say "Hey, she looks like Snow White," any more than people aren't mocking me when they say I look kind of like Ryan Gosling, to which I usually joke "The cheapest Ryan Gosling lookalike you could hire for your Netflix Original movie" which is mocking.
Doesn't really matter that Vasquez is Hispanic. She can still understand who Snow White is and make the association with Ripley's appearance, and use the name since she doesn't actually know who Ripley is, but thinks Ferro might (which infers that Vasquez went into cryo before Ferro and Ripley).
Maybe I just don't immediately get offended by every inference made to someone's personal appearance in a generic associative fashion. Suggesting someone looks like Snow White wouldn't typically be considered an insult without some other demeaning context (such as her being pale, or helpless, etc). But there's no such context in that scene. She's literally asking it to another pale skinned white woman with short hair, who doesn't have any similarity to Snow White, but whose name she does know and is familiar with. She even then sarcastically says "How pretty" which is a reference to Snow White being the "fairest of them all."
There's clearly a middle ground between skhellter and Kradan projecting sexual attraction onto the scene and you projecting a racially motivated insult. That middle ground being "Who's the woman who kinda looks like that Disney character?"