Normally I'd be right with you on this, but this time I'm going to have to say "read the comic before you judge."
Phil and Kaja Foglio (the husband-and-wife team who create Girl Genius) like drawing scantily-clad attractive people. They are refreshingly egalitarian about this. In the comic, the two men who are smitten by Agatha's genius have spent most of the last three volumes or so running around with no shirts on for various reasons. It's starting to look like a harem anime in reverse. A major supporting character (Maxim) exists because Phil drew a sexy-bishounen Jägermonster (like an orc, kinda sorta) as a joke, and Kaja liked him so much she insisted on putting him in the story.
On top of that, the story arc is basically about a teenage girl rising from humble origins to become a one-woman continental superpower by native genius and force of will, and while she's not disinterested in romance, she makes it abundantly clear that she's only interested in a man who can accept her as an equal, not a pawn or a trophy. Her suitors are both powerful men who started out wanting to rescue and protect her and wound up struggling just to keep up.
Bottom line, there is nothing inherently wrong with putting sexy ladies in a comic if it's done in a balanced and respectful way. There's not a lot of comics that pull that off, but Girl Genius is one of them.