It's mainly due to the fact that the website checks your IP and compares it with VPN blacklists. So most IPs from VPNs are on a blacklist as they are handed to multiple users who can do questionable things with it. It's hard to find a VPN with a clean IP that isn't already on a blacklist. And then, if you don't use a VPN, the site has your real IP. So not sure if that's a better result for the test.Thanks for making me try harder. It turns out that even my ESR default config (Enhanced Tracking Protection on) in private windows works against this if I change the IP via the VPN. It doesn't work if I’m not using a private windows and doesn’t work if I don't change the IP. I guess Tor's implementations at work!
Some VPNs offer an IP rotation feature that changes your IP regularly. But then again, from my experience the site still detects that you are using a VPN and maybe even which VPN provider. Didn't find a good overall solution yet.
