Thomas Edison: 'You Don't Understand American Humor'

When Tesla finished working on a project for Edison and went to accept his 50,000 dollar payment, this DVD says Edison laughed and said something about him not understanding American humor. Was Edison basically saying, "you're a foreigner and I just pulled one over on you...cheating you out of your rightfully earned wages - no one is going to believe me over you..." So Edison was a heartless bastard who stole Tesla's time, money and ideas?