He Doesn't Like Elmo?

Elmo's just a kid or a baby (I mean I think that's what Elmo represents) and JP doesn't like him because he thinks he's a coward? Like wtf?

He called him 'milksop' which means indecisive/cowardly. Why are these two words related? Like if I'm indecisive about whether to pursue something, a career say because it's a risk. That makes me a coward?