It's not about accepting the evidence. It's about making sure we interpret it correctly.

The main question to ask is this: why exactly do mandatory helmet laws reduce bicycle usage, and what needs to be done to address it?

Is it that helmets are too expensive? (They aren't.)

Is it that they are too difficult to put on and take off? (They aren't.)

Is it that they are too uncomfortable? (Maybe, but not any more so than seat belts, and yet most people aren't arguing against seat belt laws.)

Essentially, I'm not against accepting the validity of the evidence from these studies. I'm simply against the mentality of "mandatory helmet laws reduce bicycle usage, therefore we must not have mandatory helmet laws." That conclusion is too simplistic. The topic requires further study.