Wait, is it wrong to like an idol based on looks? There are many factors for liking an idol, but how pretty or hot she is, counts as a valid one I believe. That's true specially for men, and even fangirls fawn on how kawaii a girl is (specially in Japan).
One can like a girl for being batshit crazy, while some others don't. Some like momo's burikko chara for instance while some others hate it, and about looks, I think almost every culture favors good looking women/men in TV, music, advertisement, modelling and many other industries...
So Starra, don't feel bad with about it, anyone can like/dislike his/her idols for her own reasons.