Why did Hermie do this to Joe?

Joe and Hermie are sitting in a corner of a restaurant. They discuss the Screen Writers Guild:

Joe: Hermie, the guild's in its infancy. It needs you.

Hermie: You're telling me. What writer failed to notice the Screen Writers Guild needs an apostrophe? As Groucho always said, "Never belong to any club that would have someone like you for a member."

_{Hermie dips Joe's tie into coffee}