Before Trump ran for president, he was just a media gadfly. But running for president and becoming president supercharged that. Then you had the rallies, the clothing, the alternative facts, ect.. That’s when it became a cult.
Yes, Trump incorporates white nationalism (and a hatred for non-whites) into his rallies. But that was in the GOP before in the form of Pat Buchanan and Tucker Carlson. He just expanded it.
The Trump cult doesn’t have much to do with sex. But many others do. Many other cult leaders such as David Koresh and Jim Jones sexually exploited their cult members.