Do kickstands damage the frame by being used?
I have 36 years of experience using kick stands on cro-moly (steel) and aluminum frame commuter bikes and several years working in a bicycle shop in which time I have never seen any such "warping".  Its the kick stand itself that may be in jeopardy when the bike is "laden down"; there are center balance kickstands for tandem and other heavy/awkward bikes.
The more likely damage you will get from a kickstand is from over-tightening where it is attached to the frame.