Well, it is 25-50% of the nominally 4% fat found in whole milk, and I’m pretty sure I’ve read that “whole milk has twice as much or 100% more fat” or some such. (I think the normal percentage has dropped a bit in recent decades, to the 3-3.5% you cite.)
But yes, the idea that 2% or even whole milk has some whopping additional amount of fat and calories is a common misbelief.
When I worked for a place that bought cream, we had one person that had cream so thick that you could hardly get the stir rod into it. It tested close at some ungodly high number but, unfortunately, we could only pay up to 10% butterfat.
Then we had the ones whose cream was nothing but water and didn’t even register on the testing scale.