Without regard to the broader point* in the particular case of Leo, I’d be surprised if he had great k-12 science education. He was a child star already at that point, right? Only so many hours in the day.

Of course, it isn’t a universal rule, see Dolph Lundgren, etc etc.

* I don’t care if the actor delivering an environmentalist message in a movie is actually good at science for the same reason I don’t care if Keanu Reaves knows king fu.