Nah, 36 years and counting.
I shouldn't even humor fitty here, but...
'backing your partner' has nothing to do with jumping in and defending
his initial call to a rat. If there's a banger at 1B and the HC runs out to fuss at BU, do you as PU sprint down the 1B line to interpose yourself before the HC even gets there?
Hell no. You let your BU take care of business. Now, if it gets ugly, or the HC is ejected or if his minions show up, sure you move up there and peel off the flotsam and/or guide the ejected one out of the scene. But you aint there being your BU's lawyer while the initial call is discussed. This is like Ump 101.
Now, here, the PU is watching the tag at 3B (and missing it, but thats another story)...then the BU makes a call on a missed base the PU never saw. The HC gets upset about the missed base call, which the BU hosed by yakking about it loudly.
That's the BU's mess, and he gets the first crack at fixing it. It would be more embarrassing to try and 'save' him from it. But then, you know all this....
You are free to continue with the armchair psychology, though