Originally Posted by
Akataras
I don't personally see the appeal of it, but it's for different reasons than what I'm about to outline, since I'm about as masculine as a frilly tea cosy.
There are a lot of heterosexual males in this world (I swear all the cute ones are, it's infuriating. :P) and more than a few of them aren't at all secure in their masculinity. Anything remotely feminine or child-like will generally make them uncomfortable on a subconscious level, which causes them to act out whenever anything feminine that isn't a woman enters their eye-line.
If something is stereotypically for six year old girls, seeing other males liking it en masse (As seems to be the case with your lot, in my experience the grand majority of fans are male, or at least the most vocal are) sets of that sense of unease and insecurity. Anything that is supposed to remotely feminine is by default something a man shouldn't be associated with in their mind. This creates passive aggression and hostility toward anything of the sort, in their subconscious insecurity in their masculinity and status as a male, stereotypically feminine activities, particularly those typically associated with kids, become an immediate threat to their psychological security and gender identity.
That's the complex version at least, and not true for quite a few people. Society seems to feel the need to bind everything to a gender or gender role, which is the source of a lot of antagonism in our world. At a base level, it comes down to insecurity in their own gender status (and possibly sexuality in more extreme cases) and being exposed to anything that could "threaten" that status causes a negative reaction.
Like I said, I have my own reasons for disliking the show and the concept of its mass appeal, but I think I've bored you all enough with my quasi-psychological ramblings as it is.