(2) Unless the catcher is in possession of the ball, the catcher
cannot block the pathway of the runner as he is attempting
to score. If, in the judgment of the umpire, the catcher
without possession of the ball blocks the pathway of the
runner, the umpire shall call or signal the runner safe.
Not withstanding the above, it shall not be considered
a violation of this Rule 6.01(i)(2) if the catcher blocks
the pathway of the runner in a legitimate attempt to field
the throw (e.g., in reaction to the direction, trajectory or
the hop of the incoming throw, or in reaction to a throw
that originates from a pitcher or drawn-in infielder). In
addition, a catcher without possession of the ball shall not
be adjudged to violate this Rule 6.01(i)(2) if the runner
could have avoided the collision with the catcher (or
other player covering home plate) by sliding.
This is the rule as it is written currently in the 2022 rulebook. Even if I buy that Kirk was "blocking the pathway of the runner" without possession of the ball, I think both exceptions to the rule (legitimate attempt to field the throw and runner avoiding the "collision" by sliding) would apply.
If what Kirk did is blocking the plate, the umpires don't understand the rule at this point.