>>42326197
Due to cutie marks, erfs and unicorns are also accepted to be cheerleaders if they're talented at it, though the majority of mare cheerleaders are pegasi.
Mare cheerleaders are not weird because those skirts enhance mares' natural extreme sexiness, making colts weak and pliable, thus boosting the chance of success of procreation with the "fairer" gender. It also boosts morale for their mare friends, and as we know, mares are always willing to make their friends happy, because friendship is magic.