Stupid plays?

I haven't been able to play too much lately, because I've been travelling (visited Lake Garda and Venice in Italy). However I got back in business and played some HU SNS.

I am curious why betting all-in to win a small pot and postflop min-bet/raise are very common with opponents on the levels I play. I think these moves are quite clearly bad moves.

It seems that there are a lot of players who min-bet flop, turn and river oop. I am curious about where have these player learned that 'move'. Usually they don't have nothing or have a bottom pair, so I guess it is kind of a blocking bet (but they telegraph their hand). Most of the time when I raise them they fold.

The other play I encounter a lot is an all-in move when there's not too many chips in the pot yet. This can happen on any betting round and as a raise or as a bet. I am really puzzled about these moves because I cannot really think about a situation where a bet like this (over betting pot like 10-20 times) is really profitable. After-flop against these opponents I just wait until I have a monster hand and let them donate their chips to me.

However preflop it is not so straightforward. I had an opponent who reraised all-in quite a big percentage of my bets from the button. I had to folding hands to get a hand I could call with. I folded several Ace-8 or worse hands because I didn't want to find myself dominated. I am not sure wheter that was a wise thing to do, so I'll have to do some digging with PokerStove (and read the tables in the back of David Slanskys "No Limit Hold'em") on odds to know when it's +EV.

Anyway, the tournaments have been going quite well. I reached 100 games in $2 and have now decided to play only $5 tournaments and better.

So here are the stats:
$2: 59 won, 41 lost
$5: 17 won, 15 lost