So? In a battle, they'd both get shot down easily enough.
In battle, the computers reject those targets as ground clutter. In the days of smart bombs, it is smarter to not get in the cross hairs in the first place.
A funny thing about kevalar, you can't blow a hole in it with a .44 mag, but you can stick a knife right through it. So a guy with a spear wearing kevalar on a horse is of more danger to a guy in a foxhole with an M16 than visa-versa. Just re-picture the pajama parade over the hill towards ya at midnight, only this time they are on horses and are bullet proof.
Nasty.