I’m guessing that 2 cm/year is about as ridiculous as it comes in terms of plate tectonics actually doing anything.
I don't understand what's ridiculous about it.
Please note it says meters, not centimeters.
Sure, but only when mountains or buildings are in the way.
The measurements aren't being made in buildings or valleys, so buildings and mountains aren't a concern. The measurements are being made continuously over months and years so weather and satellite positions aren't a concern - we'll just take the measurements from the clearest days and the strongest signals.
So is America really moving away from Europe at, 2cm/year?
Yes, without any scientific doubt, it is. The fact that, in your ignorance, you find the idea risible is not evidence that it is wrong.