I did get a little irate, but not in front of the kids. I have never attempted to coach my kid. I've never been to a basketball practice until that one day. I have observed many of her volleyball practices without incident.
Well, you've answered your own question. You got irate when you (with all due respect) were in the wrong. You became a "threat" at that moment.
Go to the games and root (positively) like hell.