The people who consider themselves "on the fence" aren't enabling the extremists. They are orphaned and alienated by the extremists in all parts of current politics. They aren't the ones trying to storm the capital or burn down federal court houses.

In any grouping of humans, there are bad actors and good actors. Using the bad actors to characterize the entire group, when they're a minority of that population is how you create stereotypes that break-down discourse. Empowering and encouraging the moderates in your opponents camp is is diplomacy 101. Insulting them empowers your enemies.

That's the same logic used to say all young black men are criminals, all young arab men are terrorists, all white farmers are racist, etc...