I wouldn't be too surprised if Roddenberry took this position in response to outside questions once the decision was made, but if so it's a bit ironic given that it's also been widely reported (including by Stewart) that Roddenberry was openly anti-Stewart during the casting process for not having the look he wanted, in part because of his baldness.
In my younger years I had my head buzzed to a near monk length (I was pretty obsessed with Buddhism at the time) and it did not look right. Friends commented that I looked 'intense.' While perfect for the monk persona, I was going for the more badass tough guy look. It was a tough few months.
Also, facial hair helps a lot, which I am unable to grow.
So I look forward to hair plugs if I ever start going bald.
Jeff Bezos, Steve Jobs, Jony Ive are all media darlings in the tech industry, so clearly being bald isn't an impediment.
If you look at the acting world, Bruce Willis, Jason Statham, Patrick Stewart, Vin Diesel, Dwayne Johnson all make it incredibly clear that baldness doesn't stop you from being considered a sex symbol.