The Pez Co. is digging for $$$$$. That's all there is to it.
Destroy someone's work of art because it looks like what you sell? No way. Art is communication, it is expression and commentary. The couple happens to be making a comment with the Pez design -- but there is no competing business here; it's a one of a kind work and nothing more than a statement.
I doubt Pez have a legal leg to stand on, in any case. The Pez lawyers can go take a long walk off a short pier.