It's a simple overreaction on their part, really. They're bombarded by fans who ask for more minority characters all the time, so their immediate decision upon creating them is to shove their minoritiness our faces.
Fans: "We want more black and Hispanic characters!!"
Marvel: "We created a new Ultimate Spider-Man, and he's both black and Hispanic! Do you see how Blatino he is? See? Just like you asked? More black and Hispanic characters!"
Fans: "God, Marvel. Why is it every time you make a new minority, all you can talk about is their race?"