That is just wrong. For a start there is no such thing as 'background compression you get with a zoom' there is just perspective, secondly, perspective is not related to focal length but position, and lastly, at 35 and f2.8 they have identical imaging characteristics.
Call it what you will, you are probably right, but on a tightly zoomed image on a ZOOM lens you get a look that you don't get as easily on a fixed lens. In that particular reference I was not comparing 35mm to 35mm, but aiming more towards a fairly wide general statement.... I gave up my 35 prime because i liked how my zoomed images looked in tight spaces compared to the images from a fixed lens in same space, Gave up sharpness in the trade.If the 35 is worse than the 24-70 at f2.8 there is something wrong with it, There isn't a huge difference between the two, but the prime should be slightly better.
The 35 is better at 2.8 midframe and the 24 70 II is better in the corners, center is basically identical... Using your chart link...
Focal length does affect perspective .
At the same settings there is no difference between a zoom lens and a prime lens background compression.
I don't know what you mean by "on a tightly zoomed image on a ZOOM lens you get a look that you don't get as easily on a fixed lens". Some people are confusing "more zoom" with longer focal length, shorter focal length or more magnification. Are you?
"aiming more towards a fairly wide general statement" sounds like you don't know what you are talking about .