Fair enough, but there have been studies using ketoconazole and zinc shampoos (both of which kill p-acnes) showing regrowth. Other studies show that knocking out the immune-system or using topical anti-inflammatories (cetirizine) promote regrowth as well. So it's probably not the bacteria per-say, but rather the inflammation it attracts.
True, but ketoconazole is an anti-fungal, not an antibiotic. Maybe it has some antibiotic activity but that isn't documented that I know of. I suspect various zinc compounds do have some antibiotic activity though.
I guess my point was, since we don't know which is the cause and which is the effect, a reasonable next step would be to give a bunch of balding men a course of tetracycline which is known to be effective against dermal p-acnes infections and see what it does to their hair population. There's really no reason to guess about this. We know a number of ways to combat that bacteria. Try one and see what it does. There's no reason for speculative treatments like blue light or electricity. We've known how to effectively kill p-acnes for a long time now.
Also, I'm someone skeptical due to the fact that over the decades millions of people have been put on long term courses of various antibiotics which should have been effective against p-acnes. Surely some of these were balding men. Unfortunately we don't have a lot of anecdotal stories about guys regrowing hair whilst on antibiotics.