Let's set aside the fact that the intentional walk has basically gone the way of the sacrifice bunt as a largely discredited small ball tactic in the first place.
Miguel Castro is not exactly chopped liver, or as you might put it, "some random lefty" (although Castro is a RHP). He's a guy with a fair amount of red on his Savant card, especially when it comes to inducing soft contact. And if a right-handed-pitching soft-contact guy can't induce soft contact from a right-handed-hitting 39-year-old hitter who'd been making soft contact all day, a guy who already was 0-for-3 against him lifetime, then what is he doing out there this late in a one-run game?
Instead, Boone elected to four-finger Miggy so Castro could face basically our best left-handed-hitter. Granted, he was on an 0-for-18 skein, or something along those lines, but Boone still gave up the platoon advantage to face a good hitter, and he got burned. Plus, in the Scrooge department, Boone robbed the hometown fans of the opportunity to see a living legend hit a milestone goal in front of them.
When I add all this up, the result is Boone pushing a button because his finger happened to be itchy and he wanted to come off as a brilliant tactician, except that instead he was just too cute by half.
You can choose to look at it as the right move that just happened to go wrong this one time, and that's your opinion, and you are entitled to that.
But it doesn't mean you are right. 😄