I think that it is because if they dont complain about it it seems like they are okay with it and therebefore stop begin "Manly" because they are okay with a "Children show". Funnily enough, I found people who admit to like MLP or who have at least watched it more manly than haters, because REAL man donīt care what people think. They like what they like.
I'm also not a fan of This Day, as I felt it was ok but not as phenomenal as everyone made it out to be. Everyone is entitled to their opinion, and calling someone a pony hater isn't going to change that.
I like the show and I've met people who take it way too far and would make me hate the show if I didn't already watch it. There are those who act like their thoughts on ponies, pony fanfiction/theories and pony memes are incredibly important and people who don't listen are just "haters."
These kind of people are the worst kind of any fan, no matter what the fandom is.
My friend always makes a big deal over me liking MLP but never watched it so he one day asked me an episode to watch, I had no idea so just recommended Lesson Zero since I really liked it, half an hour later he comes back saying he wanted 20mins of his life back, ok if he didn't like it fair enough but I'm convinced he sat there not really watching it just thinking "This is stupid" "I hate this" etc.
My point is, we should have a live-and-let-live approach, instead of berrating those who express their opinions. It just seems to me that remarks like that are hostile towards those who did like the song and vote on it, that's all.
Example, do I like Cupcakes? Fuck no, I despise it. But I don't neg-mod posts or yell at anyone who does like it. It's their opinion, they're entitled to it and don't go stirring up trouble for no good reason.