I'm strongly disagree with this, in the general sense. The number of bald male sex symbols is INSANELY small and all of those guys would look better with hair. You only say they don't because you're so used to seeing them without hair. This is cope, plain and simple.
Hair is possibly the most valued aesthetic characteristic there is after the face. There are fairytales, sonnets, songs, etc. written about women with amazing hair and in media, how often do you see a NW4 prince charming? Never.
Hair frames the face, it adds character and individuality, can be attractive all on its own, etc. The men who generally do look good bald have very specific face shapes if you pay attention. I think it's logically inconsistent to say that you weren't attractive to begin with if you're not when you're bald, when in the latter case you are MISSING an incredibly obvious aesthetic feature.
A while ago, I was arguing with David about height vs other features and when I googled something like "Would you date a 5ft 7 guy?" the FIRST thing I read was this woman saying "Yeah, but I hate when they look good in their picture, but when you meet up, they have a bald spot. Ew".
Here's a simple test. Chris Evans, Hemsworth, Clooney, Viggo Mortensen, Zac Efron, Brad Pitt, etc. are all considered attractive men at least at the peak of their career. Do you really think Zac Efron would look nearly as good if he was rocking the Rock's hairdo or the George Costanza? Let's all be honest here, of course he wouldn't. He'd go from being the envy of straight men everywhere and the lust of women and probably gay dudes to one of those "Celebs who used to be hot" lists.
Do you really believe this would mean he was ugly the whole time? Please.