The external ballistics table I looked at doesn't support that claim. 22 Caliber bullets have relatively low ballistic coefficients (BC). As a result, the difference in drop between a 50 gr launched from a Swift at 4000 fps and a 140 gr launched at 3300 fps from a 7mm Mag (for example) is negligible (an inch or two at 500 yds). And other more powerful magnums with higher BCs will shoot even flatter.
"In ballistics, the ballistic coefficient (BC) of a body is a measure of its ability to overcome air resistance in flight. It is inversely proportional to the negative acceleration: a high number indicates a low negative acceleration--the drag on the projectile is small in proportion to its mass."
How could it not support that a smaller bullet has a lower mass, and therefore a lower BC? I'm not discounting shape and air restance, but that aspect is minor when comparing apples to apples bullet shapes with similar masses.
Which magnums are flatter? 7mm-08 is really flat. 7mm Rem Mag running a very light bullet is very flat (as you point out). 7mmSAUM is really flat. What's flatter? They're not the flattest out to 500 yds. The varminter cartridges are flatter. Then the magnums keep going, and the varmint cartridges dump speed and drop faster relative to distance from the muzzle.
To my point, the really flat shooting rifles have the highest muzzle velocity, at the expense of the bullets having low BC (because of lower mass mainly), and they decelerate much faster (because of a low BC), making them middlin' range rifles and not long range rifles, but at those middlin' ranges they are flatter shooting. A few inches may not be a ton in your estimation, but it's flatter (flattest). The point that they're not flatter is when their speed drops below those of the heavier and higher BC bullets, but because they're faster they've already covered more distance and the slower, higher BC bullet needs to catch up, so it's actually beyond that point where they're traveling at the same speed. If you start out 1,000 FPS faster you can afford to dump speed down range and still stay flatter out to middle distances. That's simply physics. All objects (bullets) drop at about the same rate, so the one covering more distance goes farther before dropping the same amount.
I can't tell what your disagreement is. Is it you don't like they way I describe it?