I think most MLP fans are in the intended demographic. Teenage male fans are simply more salient than grade-school female fans.
If nothing else, the 'unexpected' fans are reducing your yield and may be driving out potential matches.
(If you were into little girls, would you be happy or unhappy about bronies? If you wanted money, maybe happy, if chicks maybe unhappy because on the margin, little girls may be skeeved out by bronies and not become regular readers. You know what, I should've chosen a better example for this topic than MLP.)
Thus spake Eliezer:
It seems that many here might have outlandish ideas for ways of improving our lives. For instance, a recent post advocated installing really bright lights as a way to boost alertness and productivity. We should not adopt such hacks into our dogma until we're pretty sure they work; however, one way of knowing whether a crazy idea works is to try implementing it, and you may have more ideas than you're planning to implement.
So: please post all such lifehack ideas! Even if you haven't tried them, even if they seem unlikely to work. Post them separately, unless some other way would be more appropriate. If you've tried some idea and it hasn't worked, it would be useful to post that too.