What’s more damaging to democracy: a liberal calling someone racist or a conservative legislature depriving people of their right to vote based on their race?

False choice.

False dilemma - Wikipedia

But, let’s parse through some variables:

1. If a single individual calls another group of people racist, no impact on democracy.
2. If a substantial number of one party calls another party racist, there is a substantial impact on democracy. Anger results, gridlock occurs, states start talking about secession, and you start electing demogogues instead of legislators.
3. If a legislature deprives a small number of people of their right to vote based on race (say, a precinct) that’s reprehensible, but does not damage democracy.
4. If a legislature were to deprive a large number of people of their right to vote based on race (an entire state, for example), than that’s highly damaging.