I think the players like the fact that some umps have slightly different zones. As long as the zones are consistent, it can give observant players an edge.

Nothing in the rules of baseball says umps are allowed to make their own zones. They are instead saying they want to play a different made up game

The game as it's been played for 120+ years, though.

Oh then are you suggesting we should get rid of all the other things from the last 120 years like aluminum bats, cleats, safety bags, helmets, instant replays, etc? Chess needed rule changes for hundreds of years. And ABS isn't even a rule change, it's just playing by the same rules more accurately. I don't understand why baseball fans are modern day luddites

Well no. The rule itself has changed several times over the years. It now reads: > The official strike zone is the area over home plate from the midpoint between a batter's shoulders and the top of the uniform pants -- when the batter is in his stance and prepared to swing at a pitched ball -- and a point just below the kneecap. https://www.mlb.com/glossary/rules/strike-zone Which, when you think about it, isn't really all that precise. Where exactly are the shoulders in a stance? How is a "kneecap" measured? What if the batter hops around a bit when he swings? I hate to break it to you, but the robo-ump is probably guessing too, at least on the high and low calls. And it's not so much that they call the rule differently, but they are human and see the strike zone differently.