If it attacked the surface, it would have to contain a strong solvent.
AFAIK these products are simply fine abrasives in a gel. Any abrading is
done by the user in the removal of the dried film, so you might as well
sand in the first place

I'm sorry, but you are completely wrong. These products are completely
liquid; no gel, no abrasive. They DO attack the surface, and it is
wise to wear chemical proof gloves when using these products. "Sugar
Soap" is a trade name for finely ground Sodium Carbonate (Washing
Soda). I find that the best results are obtained if the solution is
applied with the type of kitchen sponge that has the green
"Scotchbrite" face; this increases the penetration of the solution. It
is very important that the surface is thoroughly rinsed after using
the solution.