> More importantly, however, this is an example of the "you're already doing it so it's not a big deal" fallacy

I'm not saying it's not a big deal, I'm saying it hasn't gotten much scrutiny, at least relative to comparable innovations in the past. E.g. when airports introduced body scanners, Jeffrey Rosen wrote an entire book about this called The Naked Crowd. Where's the equivalent scrutiny for iris scanners?