There's at least one plausible effect that could be causing it.
People mostly stay at home right now. Not necessarily gaming, but just using their desktops more often. And if you own a VR headset, it's probably connected to that desktop.
That said, it still surprises me that 1% Steam users have VR headsets at all.
Of course. And people use Passmark or Mindfactory.de data in the exact same way - I don't remember you complaining.
Suddenly Intel gets a market share increase and "enthusiasts" go berserk. Because it's not allowed to show something like that.
But why do you think it isn't? Any proof items are collected differently?
Sure, Steam doesn't give the exact methodology. So why not look into it? Ask them?
Now you're talking about a motive. So what is it? How would Valve benefit?
[edit]
Oh, fun fact:
View attachment 151014