Chemistry question for paint stripping

Paint seals to metal better. Plastic contains oils. (that's why we have paint made especially for plastic now. It used to flake off very badly on some plastic. Today, it etches itself on, but not deep enough to cause issues, which the old paint etches would.

Effect is also different by paint types.

The alcohol (likely) creeps beween the paint and plastic here , lifting bonds from underneath rather than dissolving much it all.  Castrol, and other detergents do this. I've only removed some lettering with alcohol. How paint does come off is the key, sheeting means lift, dissolved pigment is penetration and breaking of pigment and polymer bonds.

Or, they actually use two paint types, same shade.