Being new to tourney poker, there's some plays that I just can't figure out. I know that the answer is frequently, "The guy sucks at poker," or "these are the players you want at your table". But I see a lot of good players (from sharkscope stats) make this call and I just don't understand.

Here's the situation. Bubble of a SnG. Chips are 6000, 3000, 3000, 1500. Blinds 100/200. Small stack pushes on the button, medium stack calls in the big blind and flips over.... A5?? or 22?? Obviously the small stack is going to be widening his opening range, but these hands are, at best, coin flips.

What am I missing here? I never make these calls. Just doing an ICM calculation this is huge -EV. Yet over and over again I see this call from good players. Help?

It is a bad call with A5. You're not missing anything. If you have A5 and are faced with that all-in in this situation, fold it.

Yhea the blinds would have to be much higher than 100/200 for me to make that call. 300/600 I'm calling I think, since at that point button's range is {random}. A5 > random. Also, with 4 players left and 100/200 blinds I assume you are playing a turbo and/or a very low limit donkfest? What buy-in/payout structure/site are you playing? At a Pacific mega-turbo with blinds increasing every hand then I think A5 is a call here