While you're right about the advertising, (though I don't agree with the rule at all. I don't see any problem with allowing people the opportunity to get this comic.) there is nothing wrong with him posting the pictures here. He is not violating any copyright laws, nor is he claiming anything false. If he wants to post the work of those who are drawing pictures for his company, that's his prerogative, and there is no fault in it.

What is it they say about silence being golden?