That can be done already based on User-Agent, though. Other browsers don't spoof their agent strings to look like Chrome, and never have (or, they do, but only in the sense that everyone still claims to be Mozilla). And browsers have always (for obvious reasons) been very happy to identify themselves correctly to backend sites.

The purpose here is surely to detect sophisticated spoofing by non-user-browser software, like crawlers and robots. Robots are in fact required by the net's Geneva Convention equivalent to identify themselves and respect limitations, but obviously many don't.

I have a hard time understanding robot detection as an issue of "user freedom" or "browser competition".