Not everyone feels that way. Andrew Calcutt of Spiked Culture thinks that shaved heads are a part of something he calls ultimatism. As he describes it, ultimatism is "going all the way all the time, taking what we look like to the nth degree, and not only on exceptional occasions."
If you can only see yourself as a forceful individual if you shave your head like a stormtrooper, it means you cannot really see yourself as a strong character. Lack of self-conviction is then compounded by the patent superficiality of the references being made: of course, I'm not really a stormtrooper; only joking; only me. Today the sight of so many shaven heads bobbing up and down in the tidal wave of commuters coming over London Bridge into the City of London each morning, suggests that the masturbatory mix of frustrated desire and self-mockery which expressed itself in the New Laddism of a decade ago, has now spread to the post-lads and dads among the wider population.Along with self-mockery, Calcutt thinks that "ultimatism" also represents contempt for others. All in all, a very negative view.
I've certainly never noticed the attitudes he ascribes to "ultimatists" in the people I know who shave their heads, either in person or online. At least, not on any serious scale. I'm sure there are people who have those ideas in mind when they go bald-by-choice, but I'm not sure it's at all common. It screams of over-generalization.
Maybe it makes more sense if you're British?