Hmm, the article is actually quite bad. It is built on the strawman that +/- is a predictor of a player's ability overall, and not, say, whether he was used correctly and in an appropriate role. Instead of taking the stat as something the team can combine with other data such as minutes played and the opposition being played against, you took it as a characterization of an individual taken outside of the context in which a certain number was achieved.
Conclusion #1 is just silly. Of course you don't conclude player A is twice as good based on that stat alone. First of all, the absolute difference in +/- is merely ~1, and it's you and you alone who created the strawman that measures players' abilities by relative value in regards to their +/-. Secondly, the results of your analysis show that over the course of a season player A has been on the ice for 2.733 more goals for than against, and player B has been on the ice for 1.367 more goals for than against. Instead of looking at this from a perspective of the coach, who assigned them these different roles based on what his expectations were of the lines those players played on, you take it out of that context. The coach might very well have intended for player A to play on a dominating line, for which he was hoping to outscore the opponents by, say, 10 goals over the course of the season. On the other hand, he might have assigned player B to a shutdown role whose purpose was primarily to prevent opponents' top lines from scoring and give the top guys a rest. In that context, the +/- stat would have been useful in telling the coach that player B's line more than fulfilled its goals, whereas player A's line did not. In fact, since they're the same player, the numbers might tell the coach that he is better suited for that second role. In my opinion, that's useful to know.
Conclusion #2 is based on the assumption that in 1640 minutes played, the goalie just happened to have whiffed ~11 times more while player B was on the ice. This, with no regard given to the possibility that player A infuses more confidence. Or that player B was paired/grouped with different players, who might add to the explanation. Or that player A was playing against worse competition.
Finally, conclusion #3 is also based on luck. You have created this preconceived and unchangeable notion that nothing differs between the players. Fine. But you refuse to accept the fact that if two players are exactly the same, playing with and against exactly the same players and engaged in exactly the same roles, then the probability of such a disparity between shooting percentages over the course of a season is exceedingly small. Extending such generosity of doubt to other stats, then you pretty much can't take any of them as a predictor of anything. Because when plotting the distribution, pretty much any value for any stat will have a certain probability to occur, no matter how small. If, however, you know going into this that variability in +/- up to a certain number, determined by whoever wants to interpret the statistics, can be explained by chance, then that person will have no trouble realizing that the discrepancy that occurred actually could occur due to chance and that no firm decision will be made based on it.
Acting as if goalies' random flops and whiffs raising/dropping a single player's +/- to a significant degree over a sustained period of time is any more likely than an asteroid hitting you in the face tomorrow morning 7.50 AM MST. Cute.
