How come many Americans sided with the Allied Powers even though the United States was neutral?

Because of their pact to always help them if they were ever in a fighting situation. While they sided they only gave them materials it wasn't until Pearl Harbor was bombed by Japan that the U.S. jumped into war.

Explanation:

The gradual German aggression.

Explanation:

The main reason was due to German unrestricted submarine warfare and events like the sinking of the Lusitania. Germany had also sent a telegram to Mexico to exchange a military alliance. British propaganda had been advocated in the US as well showing the war crimes that the Germans committed in Belgium. This forced the US to intervene as the war was at a stalemate.  

most people were factory or company owners.

“the iliad” (gr: “iliás”) is an epic poem by the ancient greek poet homer, which recounts some of the significant events of the final weeks of the trojan war and the greek siege of the city of troy (which was also known as ilion, ilios or ilium in ancient times).