Yes, it seems like an oxymoron but quite often we do see paint that behaves this way. Probably the most glaring case is the C6 Corvette. It's very easy to inflict fine swirls into Corvette paint but polishing them out is exceptionally difficult. The physical mechanisms of scratching paint and levelling paint are very different.

About the only analogy I can think of is comparing a stick of butter to a piece of steak. Using a sharp knife put a shallow cut into the stick of butter. There's your "scratch" - easy enough. Now do the same to the steak. Not a whole lot more difficult, really. Now let's remove these two scratches by levelling the surface. Drag you knife across the top of the stick of butter, removing a shallow layer of material. Continue doing this until you've levelled enough material that the scratch/cut is no longer visible. Not hard at all, huh? Now try that with the steak. Can't do it, can you?

It's the difference between slicing into a surface compared to abrading it away. My Miata would scratch rediculously easily but it also polished out with ease. My PT Cruiser doesn't really scratch easily at all, but when it does the defects are very easy to eliminate. A Corvette will scratch easily but be a ***** to correct.