The data you are missing is the fact that an average of 20% of the Trump rallies are registered dems, 26% in AZ last night. There has been a major party realignment in the Trump era. Even the union bosses cannot hold out from their members shift and are, albeit slowly, moving republican. (Public employee unions excepted.) Anyone thinking the voters are the same as 2012 is beginning any calculations with a faulty start.
If you want a candidate who is not at all friendly with the idea of communism, there is precious little choice in the Dem primary lot. It would not surprise me if a lot of Democrats are looking at Trump. He would do well to minimize his behaviors which are a turnoff to them. And, you know, when he gets up to pee at 2AM, leave the phone on the nightstand. Dude is addicted to social media. And he's pretty good at social media if he were just a billionaire real estate mogul and reality TV star. As president, people want someone more even keeled. And it's okay to want a sane president.