Revealing mistake: After Bluto knocks Popeye out and he falls into the water, Bluto goes to jump in after him. Watch the water. Popeye just landed, but the water is really calm. And when Bluto hits the water, it's right on top of a face-down floating Popeye. As Bluto hits, Popeye's body bends almost in half backwards, revealing that it's a foam rubber mannequin.
Revealing mistake: When Popeye shoves the Taxman backwards, watch carefully. When the Taxman goes sliding down the ramp, just before he hits the water you can see the board that he was sliding on. Also, there is no motion from his arms, legs, or head.
Revealing mistake: During the fight, Popeye ducks Oxheart's swings. If you watch carefully, it appears to be the same swing repeated multiple times from different angles.
Revealing mistake: After knocking Castor out, Oxheart kicks the unconscious form out of the ring. As the body flies past the camera, the dummy used must have bumped the camera because it shakes for a second or two.
Revealing mistake: At the end, in the fight with Bluto, Popeye is facing Bluto on one side, goes underwater, and pops up on the other side. If you watch closely, the figure that goes under is the stunt double. Nobody can move 15 to 20 feet underwater in three seconds. Also, before Popeye comes up, you can see him underwater while the other figure goes under.
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.