Bigus Dickus
Regular
The vast majority of these little puzzles are extremely contrived. I mean, things like the "A man is performing his job when his suit tears. Less than 5 minutes later, he's dead." or the "A man eats food which is not poisoned, but causes him to die." Both of those are perfectly fine, and have rather acceptable responses (though the second one has an alternate answer which is a bit ... eeeh.).
But puzzles like the "A man meets a one-armed man on the subway, who then pulls out a gun and shoots him." one is just all too contrived. The worst one I've ever seen had to be that "A man is dead in a room with a small pile of woodchips and sawdust." That's just not a puzzle by any means.
None of those are legitimate puzzles of any sort. For each, including the one in the OP, there are dozens of plausible explanations, many equally likely relative to the others. I can think of many things that would tear a suit and kill a man. Lots of things can go wrong eating food which causes death. There simply isn't enough information in the "puzzle" stem to differentiate them. So saying that not giving the "expected" answer is wrong is just absurd.