The thing is no ones knows what the exact specific cause is and to be honest I don't think we actually ever will. The speculation is that 5ARis negatively impacts males (especially synthetic 5ARIs) and there is plenty evidence to back this up. So to look at another drug which impacts 5ARi and associate similar or the same symptoms to finasteride is pretty reasonable IMO.
The solution with herbs and prohormones is at least you are pushing yourself in the right direction to rebalance to homeostasis. We know the prohormones (androsterone/epiandrosterone) that are being cycled were lowered from finasteride. So whether you are readjusting the receptor by replacing these hormones again into your system or simply stimulating 5AR again they do seem to help.
Allopregnanolone is only a small piece of the puzzle downstream. Here are all the hormones finasteride negatively (negative sign) impacts: