The fact it is a revenue source has more to do with people not following the law than the system.

The problem is cities reducing the timings, because it'll go from green to red without sufficient time to safely stop. The whole purpose of the yellow light is to give you wiggle room to either stop or get through the intersection before the next cycle. If a sudden red forces you to slam on the breaks hard enough to risk being rear ended (or worse in icy conditions risk sliding into the intersection)

Plus if the timings are tight enough someone trying to stop/complete their menuever might find themselves in the intersection with opposing traffic now trying to enter

Traffic cameras are just trying to put out a greese fire by throwing water on it. If you don't know better it seems like a good idea, but in reality it just makes the problem worse