I think stopping RLJers has a number of useful functions.
It is promoting road safety. We can argue about the number of peds knocked over until the cows come home, but this isn't just a case of other people harmed by RLJing, but the harm an RLJer may cause to themselves. Sure, it's safe 999 times out of 1000, but then just once a car leaves the other exit a bit quicker than usual...
Also, motorists do sometimes perceive cyclists as able to get away with whatever they want, cycling on pavements, the middle of the road, jumping queues, jumping lights. Some motorists get annoyed that while every little transgression they do is monitored by speed cameras, traffic cameras, traffic cops and the like... if the same is visibly true of other road users than it reinforces the idea that we are all equal.
Just my two penn'orth.