In this case, their interest is aligned with the public interest, so nothing wrong.
Epic Vs Apple, Oracle Vs Google are also just companies acting in their own interest but that doesn't mean that the public should be unconcerned or that the people's interest won't align more or entirely with the side of one corporation.
+1. I see nothing wrong in playing positive sum games. Mullvad will ptobably gain a lot if they succeed but as long public also gains a little, I am totally cool with it.
After using Mullvad for a while now, I believe they care about privacy more than others. Maybe I'm wrong.