It's even worse than that. Very, very few people are actually centrists. Like, .1% of the population are probably true moderates.

The parties are coalitions representing people of varied opinions. And people rarely agree with the parties on every issue. But most people fall generally on one side or the other. However, some folks end up highly misaligned to the party issue assignments. For example, what party is the natural home for a militantly homophobic militant atheist? They think both priests and gay people should be sent to reeducation camps. Where do they belong?Neither party really. This person would consider themselves a centrist, even though they have nutjob fringe views from both the right and left. This is an extreme example, but it illustrates what most centrists actually are. They're not lobotomized zombies with no passion or beliefs. They have strong beliefs that simply don't align with the party coalitions.

But this reality is not how "centrist" politicians govern. Instead they try to place themselves at the exact center of every issue. Very very few human beings actually think that way. So they inevitably come across as highly inauthentic. People believe in things. If you try to walk the dead middle, you're telling people you believe in nothing. You become a living example of the uncanny valley. And people feel gross just listening to you.