When the announcer quoted the rule about a throw being necessary, I am sure she was referring to (incorrectly) the batter/runner going to first. The first time I heard her I did not catch her saying "batter/runner".

I have difficulty with the no call. I thought it was clearly interference on the part of the runner. Matters not whether it was intentional (which it appeared not to be). I agree that strategy should not be considered. Now, did the fielder have a "reasonable chance to make a play"? Does she have a rocket arm or just average. Gwarsh, does it make a difference? It appears that, interference or no, she would have had difficulty throwing the ball with any zip. However, I still think interference should have been called.

Her arm makes no difference ... but the location of BR when this happened certainly does (and we cannot see that from the video, but I did look up who the player was and she's fast). Clearly the umpire (who had the whole play in front of them) saw where BR was when F6 fielded the ball and did not think there was a play.

The only play F6 had was at third after R2 stumbled, and she didn't even look in that direction. I'm going with "reasonable chance to make a play and was prevented from doing so." The only thing that prevented her from a play was that she didn't even look for the only play she had.

The rule says prevents fielder from making a "play" Isn't fielding the ball, making a play? The rule doesn't say prevents fielder from getting an "out"
Dave

the book says, "provided the fielder had a reasonable chance to make a
play and was prevented from doing so."

Goes on to say, "Note: If both players’ actions are appropriate to the situation and contact could not be avoided, it is inadvertent contact and neither interference nor obstruction."

Providing the B/R is as fast as it seems, I think both entries protect the runner in this case.

That is the rule; you are correct. I don't see where the runner interfered or hindered the fielder from making the play, e.g. fielding that high chopper. Good no-call, not so good game management dealing with the coach. Too many conferences and too many minutes debating a judgment call. Warn him and move on.