What the hell is up with this?! What is this supposed to accomplish?!

Standard Scenario:
I have KQ and flop comes K73. I bet, muppet calls. Turn is a rag, I bet, muppet calls. River is another rag, I check. Muppet minibets, I call and he shows K6 (or even worse, a middle pair), I drag the pot with my better kicker. Why the hell is he betting a super-marginal hand when he's getting a free showdown?! Is he bluffing?! If so, what kind of hand that beats him would I fold to a minibet?! Is he actually valuebetting his TP!? Why?! The only thing he can beat is a busted draw and that's not going to call (well.. probably not gonna call..).

This happens all the time and I get really annoyed by it. I can understand stop bets or post oak bluffing, but actually minibetting when it is checked to you and you have a hand with *some* showdown value... it doesn't make sense!

</rant>

My best guess would be because he blows at poker... Are there any times I'll fold to a $2 bet into a $50 pot on the river... NOPE... Hell, even if I'm betting a draw that doesn't hit, and all I've got is Ace-high, I'll still call...