If you can stop your dog from approaching others unless you've checked with the owner that it's OK, then you should.

If you can't, then you need to train your dog so that you CAN.

It's common courtesy and common sense.

Just out of interest, is there anyone here who is saying "I can call my dog away from anything, and could easily prevent it from going over to say hello to another dog - I just choose not to"?

Because I suspect that those who are saying that dogs should be able to approach others willy-nilly, are actually justifying their own lack of training to themselves