Major League Baseball keeps rejecting the Mets’ request to have players wear special caps for one game to mark the 9/11 anniversary — and its explanation doesn’t add up.

As The Post’s Rich Calder reported Sunday, an MLB source says teams may “honor tragedies” only “during warmups and other pregame activities,” because the central office doesn’t want to get stuck “judging which tragedies should and shouldn’t be recognized during a game.”

Huh? As City Councilman Justin Brannan notes, MLB just let the Astros don one-day caps to mark the anniversary of the moon landing. So it’s OK deciding about happy events, but not sad ones.

This reeks of a marketing guy’s worry about branding: a fear that broadcasting a heartfelt honor might screw up lucrative gimmicks like the Players Weekend shtick.

Thing is, teams don’t survive in the long run without the support of their local communities — and marking major events like 9/11 is a genuine way to deepen such bonds.

Grave moments are a part of life and a part of love. If baseball’s execs can’t see that, the game is doomed.