Taunting was not only accepted, but viewed as a crucial part of the play-to-win process. A well-played hand that produced an unexpected loss for your opponents had to be accompanied by a well-played barb, and if you were on the losing end you were expected to respond in kind. It was all part of the game, and if you didn’t like the insult process you just shouldn’t play.
This is all well and good when card playing is confined to the family unit. It’s a bit uncomfortable when you sit down to play an innocent game of euchre with friends and realize that your inner asshole sees the deck of cards and concludes that it’s time for him to make an appearance.