A VPN moves your traffic through someone else's address. Every signal on this page is read by JavaScript running inside your browser, after the tunnel has already delivered the page. The tunnel never sees it and cannot change it.
That is why a site can recognise the same browser across two different exit addresses. Your GPU string, your font list and your canvas hash stay put while your country changes.
The rarity labels are our judgement about how identifying each signal usually is, based on how the browser exposes it. They are not measured against a live population of visitors.
We do not tell you "one in N users". That number needs a large sample of real visitors to compare against, which would mean collecting and storing fingerprints from everyone who opens this page. Building the surveillance database to tell you about surveillance is a trade we are not making, so the page shows you what is exposed and stops there.
The Tor Browser makes every user look identical on purpose, which is the only approach that works well. Firefox's resistFingerprinting does some of the same. Brave randomises canvas and audio per session and per site.
Blocking one signal often makes things worse: a browser reporting no WebGL at all is rarer than one reporting a common GPU, so the block itself becomes the identifier.