Of course populism doesn't mean LITERALLY popular, but they're part of the same family and that's the point you're completely missing. Also using the US as an example of democracy is hilarious.

How am I wrong? It's a popularity contest in which the most popular (or least unpopular) candidate wins. Populism is encouraged by the current system in which the winner takes over all of the most important executive roles in the government.

presidential elections are about the most popular politician winning, so populism is a logical consequence of that