I don't thinkthat it's disrespectful because you aren't forcing anyone to go or dress in any particular way. If a girl wants to dress really sexy and go along with the theme that's great for her but if she would rather calm it down that should be cool too. I think it's a funny idea and I just think no one should take the words too seriously.
Also about the words yeah it's a bit harsh but like you also need to see there are a lot of other racist ideas such as a white trash party or people can even think a Luau is kinda racist. It's bad when people take things so seriously and take the fun out of things by making them controversial.