I started primary school in 77 so it must have gone on in some areas for a lot longer than others because they had only just stopped doing it where I went to school and some of the teachers still encouraged right handedness.I'm surprised. You are a heck of a lot younger than me. I'm not left handed but I knew fellow pupils who were and none were ever made to write with their left hand. And I'm talking about UK schools the 50's and 60's. Maybe it was the private school you went to?
Off topic..