We know now that even small hits or blows to the head over time can have long term damage, hence the recent controversy in ice hockey, American football, boxing and pro wrestling. So it’s very possible that the Three Stoogee were suffering in some sort from the slapstick.
However, the general public’s knowledge of CTE didn’t really make grounds until the 2000s, so the book suggesting that Moe was being careless I don’t agree with.