It could have been worse-- you could have been called to forfeit the hand instead of getting your chips back.

I'm not an expert but I think it falls under the 'every player is responsible for protecting their hand hand' general rule. If you let your cards touch the muck (or if you let the muck touch your cards, in this case?) then it's on the player.

They couldn't tell if you get dealt a 3rd card preflop so it looks like a good call here. Not much anyone can do.

It's only barely related to this, but I'm reminded of a maniac/retard ball cap&sunglasses wearing kid in Vegas at Mandalay Bay that made a nonsensical play on the flop after it went bet-call-call, he called, it was raised behind him, back to the bettor who folded, another fold, a call, then the kid decides to push in (his rather short stack)-- except the dealer accidentally mucked the kid's cards when he collected the initial bettor's mucked cards. He didn't get his call money back, but at least he didn't lose his push money.

The board was 775 and the kid bitched and carried on about wanting to get his 75 back. That is, until showdown when the 2 people in the pot had J7 and A7.

Sorry for the tangent. I just remember that kid from that trip so clearly.