Curt Schilling is standing by his President -- telling TMZ Sports Donald Trump is NOT a white supremacist and will continue to have his support.
Trump's been taking heat for his comments about the violence in Charlottesville -- with some claiming he was defending neo-Nazis, the KKK and other alt-right groups.
But not Schilling ... the ex-MLB star says he's seen videos of Trump denouncing hate groups like the KKK going back to the early '90s -- and he truly believes Trump is no white supremacist.
"He's been asked to [denounce hate groups] over and over again, and it doesn't matter what he says or how he says it.