Because the standards are relative to the voters, and Trump is appealing to a voting base that’s very big on misogyny and racism. That’s what they want out of their preferred candidate.
But in general, you need to look at redistricting, gerrymandering, voter suppression, all of the standard tactics that Republicans have effectively used to give themselves more weight in the presidential race. Of course the electoral college is part of the problem too. The low population red states are disproportionately represented. This has been going on for a century? Longer? The exact details have changed over time, but the general strategy is to change the rules or ignore the rules and hope you don’t get caught or if you do get caught rely on the courts backing you so that your party wins.