I suppose. I would guess (or hope at least) that he simply wasn't given the choice to just release a few tasteful products. It was probably either release nothing or go whole hog into Lady Krusty Moustache Removal System territory.
I think you've got a really good point here. Speaking from the syndicate's point of view, it's highly inefficient and a poor bargaining position if you have to get authorial approval for each and every item. Watterson probably never had a choice, it was either authorize BOTH the Hobbes doll AND the peein' Calvin doll, or neither at all.
So it couldn't possibly be that he's against merchandising, but rather it wasn't classy enough for him.
"Actually, I wasn't against all merchandising when I started the strip"