Heck, if you're willing to get really silly (even sillier than saying Protection from X blocks all mind-affecting effects), a stinking normal attack like beating you with a stick can be argued to exercise control over your mind to a degree, since being attacked (and the resulting perception of danger) releases certain hormones in your brain, most notably adrenaline.
But the language is interesting.
to exercise mental control over the creature (including enchantment (charm) effects and enchantment (compulsion) effects that grant the caster ongoing control over the subject, such as dominate person).
Implies that there are things other then enchantment affects (and possesions) that it blocks against.
I'm pretty sure there are, actually. There's one spell in Libris Mortis that uses a previously implanted tumor to control the target similar to Dominate Person. It's neither an Enchantment (it's Necromancy) nor possession, but it would still be blocked.
So basically, Protection is the new Iron Heart Surge/Freedom of Movement?