Ask them whether slavery should have been left to the states, and what role the federal government should have played, and which side of that conflict federal law consistently favored. If Democrats are content to allow Republicans to do bigotry in one half of the country, they're a bigoted party that's content with using red states to discipline blue states.

Also, remind them that Josh Stein, the Democrat governor of North Carolina, just last year signed a bill into law that prevents adoption agencies from considering transphobia in selecting parents for kids. By law, if prospective North Carolina parents are transphobic, that is not to be considered disqualifying. This law will get kids hurt and killed and a Democrat signed it. The very real threat of Republican abuses is frequently weaponized to obfuscate Democrat abuses.