When the right wing conjures a boogeyman, the centrist instinct is to take a compromise position with it in the name of "pragmatism". They either believe the right must be acting in good faith, or in maintaining unity with the right. But over time, this act of reifying that boogeyman convinces them that it's real. And in an electoral realm, when you cede the ground to the boogeyman, it's not surprising that people go with the fascists who said they could protect you from them.