Huh I've never heard that in my own experience. I'm middle aged, saw it in theaters. In fact I think it was probably the most referenced of the franchise in my world besides the scene with the opening of the Ark.
I remember being terrified as a kid with the heart stuff.
That heart scene scared grade school aged me as well.
It was after The Last Crusade had been out for a while and was pretty much universally liked. Thats when the people started talking bad about Temple of Dooms goofy scenes and cheesy special effects.