Trump's base is mostly uneducated rubes who believe conspiracy theories and are only qualified for menial work. They are either too lazy or too stupid to get an education and better themselves, therefore globalization/technology = bad. Plus many of these folks are racists and fundamentalist Christians, so they're especially angry with Obama simply breathing oxygen, and of course they're angry with progressive policies like gay marriage. If we want to make America great again, we could start by easing up the laws against tobacco advertising, maybe incentivize Burger King to add infertility drugs to the Whopper, do away with those protective fences at NASCAR races, etc.