Typically I’d be a bit snakier here, but if you’re just trying to learn about politics I think that’s a good thing and there’s lots of misinformation out there. Here’s a video of Trump’s comments about Mexicans and South Americans:

He’s referring to immigrants full stop, not a specific gang. Whoever told you that was lying. If you’re going to learn about politics you have to consider the possibility that the information you’re getting from all sources, left AND right wing sources, might be untrue or biased. Check for yourself. It’s a quick search on Youtube to hear the words from Trump himself.

Also, read the article more carefully. My entire point is that Trump support can’t just be explained by racism.