Considering that the original article is a guest commentary (not a scholarly piece) and written by someone who isn't an evolutionary biologist, the conclusion seems clear to me: Terence Kealey, a bald man, is making fun of Italian Prime Minister Silvio Berlusconi's recent hair transplant. It is precisely a "just-so story" because it is nothing more than a joke. A gentle teasing. Dr. Kealey is doing nothing more than laying out a ridiculous (literally!) justification for telling Berlusconi that the hair transplant was a mistake.

But the question is still interesting:

What is the down side for serious Darwinists to just cutting the “evolutionary psychology” psychodrama loose, and focusing on what real science can say about evolution?

There is none. In fact, many (if not most) evolutionary biologists don't seem to take evolutionary psychology very seriously, in part because even if they could avoid the ethical problems surrounding direct experiments on evopsych hypotheses, those hypotheses would still be exceedingly difficult to test well. Confounding factors abound. So it seems to me that the unwritten premise of the question - that "serious Darwinists" have (in general) jumped on board the evolutionary psychology bandwagon - is false. Instead, I think we could count, on just a few hands, the number of evolutionary biologists who take evopsych seriously. And Dr. Kealey is, rather obviously, not among their number.