Question for older British people here...

Serious question: If you grew up in the UK in the 60s and 70s, how did the schools there balanced the rabid anti-drug rhetoric with the patriotic pride of a British Empire who forced drugs down the throat of China in the 19th century Opium Wars? I don't mean to troll, I'm genuinely curious how teachers could both preach anti-drug rhetoric and simultaneously brush away the Empire's history of forcing another country to, essentially, legalize drugs...