Regardless of what this dumb party is, it's first and foremost a donation by a private person. Who happens to run Mullvad. So in the medium term this should have no bearing on the company and how it operates from their point of view. The article hints at disagreement on the board about many things. So if this news story turns into subscribers leaving by the thousands, I would sooner think the "generous" donor might be pushed or bought out.
The tech sector is run by people too. Some of them are mad. Our modern outrage economy demands drastic and public knee jerk reactions to be on the good side. If you're considering leaving Mullvad, voice your concerns to them first. Put pressure on and wait and see for a bit. If they all turn out to be Nazis in trenchcoats, by all means leave. But they could correct this internally (push out/buyout) and then there is no need to destroy an otherwise okay VPN provider just because one of the founders turned into meatball Melon Usk.
I don't use Mullvad but I have used Proton VPN and am now using AirVPN. It's my experience that if you're using VPN to stream Netflix content or the iPlayer from the UK, you'll be equally sol on other providers because the streamers have gotten better at spotting and defending against VPNs. So switching in a huff may still leave you disappointed as well.
and then fix the new mistakes it made while trying to fix the old ones and