Yeah, that's a little strange. It also seems strange that this "PFK" enforcement exists at all. Not only because of its sui generis enforcement, but also because a free kick is just that - free to be recovered by either team. So if B forms a wedge and prevents A from maybe reaching the loose ball, it seems fishy that re-kicking is never an option... which means, it also seems fishy that if A commits an unrelated foul, re-kicking suddenly goes from NOT an option to the ONLY option.
I mean, I get the LARGER philosophy, which is to reduce dangerous techniques AND reduce re-kicks in general
And I suppose wedges are only illegal when it's not an "onside kick formation," so if we're flagging it, I guess it's philosophically fair to consider A as having conceded possession, similar to the reason why PSK exists