For some reason I cannot edit my post below. [Error: Messages body contained no text (or some such)]
So...
After reading the linked site:
I guess it comes down to trusting Apple Insider. The actual page reads like an ad for Proton VPN. I didn't see any actual links to the raw data that was used by Proton ("A study conducted by Proton, using AppTweak download data from May and Exodus Privacy tracker counts...").
I think I'll forego testing this VPN. Certainly the data, if verified, is disturbing and unethical, but since I'm not using any VPN, I'm not affected by those problems. Not showing Apple in a positive light, of course, especially if they have been notified of the Proton results.