I worked in Israel for four and a half years, and I didn't get a visa in the last six months. Will this be the reason why I was refused a visa in America?

First, you tell the visa officer that you have been to Israel. Has the visa officer seen your passport? Look at your passport. You can see it there for half a year. In this case, it will definitely affect your application for the United States, because if you go to Israel for half a year, the visa officer will also doubt whether you will be there after you go to the United States. However, if the visa officer didn't turn over your passport and didn't see that you were hacked in Israel, you might be lucky to pass.