I understand that you don't. But some of us do not mind these things and/or want them. Perhaps there is a compromise (e.g. an optional global ID if you opt in to the system)

All of the forums I've used didn't focus on a single topic or subject. It was usually made up of people sharing a general interest, but there were always boards within each forum for either general discussion or more focused discussion on a particular topic like movies, games, art, philosophy, etc