First, Altuve is not a slow footed catcher or lumbering first baseman. We routinely sent those guys home to be thrown out at by 15 feet. Altuve is one of the fastest guys on the team. An excellent baseruner.
Next, the pitcher on the mound throws 103 mph gas and is a big strikeout pitcher, so the odds are high that the next batter can't put the ball in play.
Third, he took the risk to get the walk off win. If he failed, the game would still be tied with the winning run in scoring position.
Fourth, Altuve looked back and saw that Judge had missed the cutoff man and that his throw was heading toward second base.
It was very different from the stupidity that we witnessed game in and game out.