Question about the movie "On the Waterfront"?

I absolutely love the 1954 film On the Waterfront, one of my favorites. Although something about it kind of confused me. Why didn't Johnny Friendly just kill Terry Malloy? After Terry told the truth about them Johnny told him he wouldn't find any work, but was that the only thing he could threaten him with? He was perfectly willing to kill Terry's brother who hadn't done anything. Anyways, it's still a great movie, but I'd like to know if anyone has any ideas.