Other mistake: During the end of the movie, when Popeye sings the title song, if you look at the bottom right of the screen, you can see the runway type platform that he dances on until he goes off the end, and ends the movie.
Other mistake: As the people are going up the ramp to the Oyl's party, the man in the brown stops by the piling with a paper. As he bends over, there is a sound of the pelican pooping, and the man reacting to poop on his paper. The man and his paper are on one side of the piling, and the bird's tail is on the other. He couldn't have pooped on the paper unless he threw it.
Answer: One, Bluto is a bully and threatened him, after all his name is Wimpy. Plus he most likely offered to buy him a hamburger, which he would have paid next Tuesday.