NTA. Someday she is going to do that to the wrong person and suffer some really bad consequences. You need to get your wife on the same page with you.
Time to start enforcing direct consequences. “That’s not funny. It’s rude and inappropriate and I’ve asked you to stop.” Flip off the tv? The tv is turned off immediately until she apologizes to you or she leaves the room. She doesn’t enjoy it anyway. She touches or pretends to touch someone’s plate. Their food is not unsafe. It goes in to the trash or tupperware for her lunch tomorrow and she needs to wash her hands, apologize, and make them a new plate. Either the food is unsafe, or she is fine sharing germs with another person and that is why she claimed their plate by touching it. She flips off the dog. She apologizes to you for abusing your pet and being rude to something you love and goes and cleans poop out of the yard for fifteen minutes.