This is about what customers are comfortable supporting. This guy doesn't just have what many consider to be unpalatable political beliefs, he's one of the biggest funders of what many consider to be an unpalatable political party. Lots of people don't want to give money to something which they feel will in part be funneled to an organization which is antithetical to their views. Realistically, I kind of doubt Mullvad is rolling in swimming pools filled with cash getting syphoned to neonazis, but that brings me to my next point...

For many, it's not just an intellectual position but an emotional one. This doesn't necessarily mean it's wrong, but you probably won't be able to reason them out of it. It's the same reason I don't listen to Michael Jackson. He's dead and none of that streaming revenue would go to him or to raping children but...yuck.

At the end of the day, there's an irony in this guy supporting the very freedoms on the internet which are being used to disseminate criticisms against him, and perhaps inducing people to starve one of the vehicles which helps maintain those freedoms.