The relentless promotion of Miles Morales as Spider-man always seemed to me to be fueled by people who merely liked the idea of replacing a well known hero with a new one that wasn't white. I suppose they either think it's transgressive, or progressive, or some other sort of -essive or -ism that they want to support on a conceptual level.
Unfortunately, once you get past that and really examine the content, it was pretty mediocre.
Anyway, as one of these actual "Persons of Color" (Hey, I thought calling us colored people went out of style in the 60's? Thanks for bringing it back you culturally sensitive white people) I kind of find the entire episode pretty distasteful. Ultimate Spiderman was an "Okay" book. It didn't deserve the praise that got heaped upon it, and it certainly felt to me like that praise wasn't actually for the book itself, but instead because some people wanted to use the book to send a political message that they felt comics desperately needed (Because as we all know, comic books are some sort of hotbed of racial intolerance or something).
I think in the end, this probably made the situation worse. It's not like everyone is a moron and can't figure out WHY some things get tirelessly promoted despite their actual merit and yes, some people are going to be reactionary to that. In fact, it's probably entirely justified if you actually care about quality of the content of comic books instead of just the "message" you perceive them sending. While I'm certain that there were some people who were angry because they are actual racists and hate the idea of a minority replacing a white super hero, I'm also very certain that those people would be in the extreme minority. Most people were probably like me, an actual minority, that felt as a comic book reader, I was having my intelligence insulted.
My advice for people who want to turn everything into a social cause is: Don't. If you see something you approve of, then support it, but maybe be a little picky about what you support in terms of quality, otherwise it's just patronizing and you're actually being offensive to the people you think you are supporting (like me).