I think you aren't recognizing the harm of collecting this information. I might be okay with this if companies were banned from using age for targeted advertising.

However, the other harm is the recent IDScan hack which leaked 153M people's IDs. And regulation is not a solution here, we don't know how to implement a regulatory regime that will prevent these sorts of privacy disasters. Even if IDScan gets fines which kill the company (and I suspect they will not) it's not enough of a deterrent because no one will pay enough to actually provide proper security here.