Jones still believed in the virtues of Socialism and was dedicated to lifting up the oppressed, but he would no longer have the capacity to learn from mistakes, because he didn't believe that, as a superior incarnation, he could make any. In the future, anything that didn't work exactly according to Jones' desires would be the fault of flawed followers or implacable enemies, and with each passing day, Jones became more convinced that he had enemies everywhere.
And here's where he tips over the edge, from simply building an empire in service of his ideological goals, to becoming God himself. And while many of his closest followers don't believe in his divinity, they are still willing to look the other way, because they have completely bought into situational ethics, where the ends justify the means. Who cares if their leader is an amoral lunatic who is presenting himself as infallible God and sees enemies everywhere, if he can help achieve your ideological goals?