Mistwell
Crusty Old Meatwad
I imagine they were referring to attacks specifically because the monk makes the actual attacks magical, which means all their damage is magical.
True. Of course, that's to make up for the fact the monk is using his fists and feet often (though they can use some weapons), and the barbarian is using a weapon. The barbarian should, relatively quickly, obtain a magic weapon. Right around the time foes are regularly resistant to non magical weapon damage. It's kinda how the game is built.