If you 1 - think X and also 2 - think that everyone who doesn't hold the same belief is "dumb"/evil. Isn't logical to think a doctor is less "capable" (whatever that means to you) if he/she doesn't hold the same beliefs that you do ?
My take is that the polarization/radicalization that is happening in the last 10 years made the second point pretty common (i.e. to think everyone who doesn't agree with you is dumb/evil) and this is just the consequence of this kind of thinking.