Not sure which side you're arguing. Does the US even have automated speed traps? Every time I hear about them, there's opposition and it doesn't happen. I think the most recent one I heard about in the US, the plan was to issue a ticket unless the speed is at least 11mph over the limit, which seems... both fine but also kinda silly?
Red light cameras were even a big fight to get implemented back when they were a new idea, though they're relatively uncontroversial these days.
To me, the difference is that the speed limit is intentionally poorly enforced, because law enforcement knows that speed limits in many places are set inconsistently and at unreasonable levels (and I believe that's also intentional; I recall reading that limits in many places are set at the 85% percentile of actual measured traffic speed, or something like that). An automated speed trap can't judge whether a particular speed is safe for the current weather and traffic conditions.
On the other hand, it's never safe to run a red light; that's just a binary "you did it"/"you didn't do it". Yes, I know, technically it is safe to run a red light when visibility is plentiful and there's no cross-traffic within sight, but I think we as a society have accepted the idea that you just shouldn't run red lights, and getting ticketed for doing so is fine under nearly any circumstances.
