All fandoms are ridiculous, I’n sure somewhere out there there are jackasses proclaiming why all the kids and trolls need to be svelte and skinny with perfect curves and abs, and the Strilondes can only be albino or white and the Harleyberts can only be white or southeast Asian.
Yeah, all fandoms seem to have people that suck like that. Don't know if it's a fandom thing or an internet thing or just a people thing. The creators aren't entirely without blame, though. After all, it wasn't fans who hired only white voice actors for the main cast of MLP:fim, and it wasn't fans who characterized Homestuck's human cast as white within the text itself.
This doesn't make those who hassle anyone with non-white readings of these characters any less douchy, but the "I never specified what race they are" or "they're fantasy aliens/colored ponies/whatever and not any human race at all" that you occasionally see from creators and their defenders is basically bullshit when they know how much of their audience is going to assume a white default reading.
And it's especially hypocritical when the creators themselves visibly demonstrate that same white default themselves, such as when almost any new character that is deliberately characterized as non-white in MLP is also made a non-pony, whether Zebra or Buffalo or Horse. Or when Hussie refers to the kids in text as having "pink skin" or being "white rappers".
Even though I myself didn't have as much of a problem with it, I had to give Hussie some credit for pulling the Caucasian page when he realized the people defending it were exhibiting exactly the kind of unapologetic vitriolic racism that the page's critics accused it of endorsing, but it would be nice if he (and Lauren Faust, and any number of other white media creators who fail to consider the possibility of non-white audience members until after it's too late to include overtly non-white characters in their cast) had the foresight to realize this would be an issue to begin with, years ago, when first designing his characters.