I don't know, didn't all of us and our friends and siblings grow up watching Tom and Jerry, Wile E. Coyote, Bugs Bunny???....the majority of us didn't go around dropping anvils on each other, or using TNT on each other, and that is because we had a good mom or dad or both who did correct us when we DID do those things, early on.
That said, I agree with you, that if he didn't see these cartoons, he would be less likely to copy them, but my kids don't watch that stuff and they still whack each other with bats or toys or tools, when they get mad, that is how toddlers react, they are little little cave-men....it happens, you are just getting more opportunities to correct the behavior, earlier on.
Yes, your husband needs to realize that at this age, everything they see and hear gets regurgitated in their own speech and behavior. Maybe if you look up a few articles by "experts" on toddler behavior and show him that violent cartoons are not good for little kids and that parents' verbal habits are what their kids pick up on...maybe it will make more impact on him coming from the "experts" than just from you. I bet he is thinking it is "bonding time" and "guy time" for them watching the same cartoons her watched as a kid and talking about bodily functions, like poop and farting and burping.....I swear guys think these are manly rights or something. Maybe suggest some other shows or channels or DVDs your son and hubby would both like, or some other activity that is GUY-ish for them to bond over - planting a garden ( 2 year olds LOVE digging in the dirt), "fixing something" like the car, something around the house, going on a nature walk, stuff like that???
Good Luck, I know husbands can be stubborn about stuff, but they are parents too, and we have to let them do it their way sometimes, or they just feel like we don't trust them with their own kids.
Another thing you could do is video tape or record on your camera your son saying/doing the things to show your husband you are not imagining things/blowing it out of porportion.