Trump wasn’t trashing the areas those lenders operated in, and then taking loans from them anyway.
Remember?
Now if he were really to build "The Wall" AND get Mexico to pay for it, we'd be getting somewhere.
Who was doing that?
No, he just trashes the lenders themselves as well as the people to lend from them.
Trump projects his own corruption on others. Since he corrupts politicians by buying them off, he assumes that anyone who accepts donations or even those who take out loans against their own assets are also being bought off.
Trump doesn't like candidates taking out loans, because then they don't need to take money from him.