Remember this is the UCI. It's more complicated than that. In 2018 they added a 3-second time gap for finishes that end in a bunch sprint (like today).

This was so you don't have GC contenders mixing it up with the sprint trains for fear of letting a 1 second gap open. This way they can kind of sit up and not interfere with the sprinters. This is why today you can see riders crossing the line for a full minute or so in smallish groups, and they all get the same time. I think the 3 seconds is loosely enforced too.

Kinda makes senses, despite my swipe at the UCI. No need to have GC guys throwing elbows with the DQS guys.