Just a decade ago commentators said the same thing about teachers physically assaulting their students under the guise of chinuch. If a teacher is STUPID enough to put a kid on their lap nowadays, they will live to regret it. It’s the equivalent of pulling the kid’s pants down and giving petch which was also “tradition” back in the 1980’s. Baruch Hashem our community has woken up to the fact that some “traditions” are minhagei shtus and MUST be stopped.
Just like kids aren’t missing anything from their rebbe not giving petch. So too the new generation of kids will learn to adjust to the new reality. They’ll turn out just fine without sitting on rebbe’s lap!