Look I understand roping is not cool. However the game allows them to use that time however they like. You may consider it wasting your time, but it was their time to use however they wanted to. Turns are set up to last up to a certain amount of time. Hitting the end turn button is the choice of the player on their turn.
Just because they are empowered to rope others because the game lets them, doesn't make it an acceptable thing to do. It's a game where both people are expected to actually play it. If the guy was carefully thinking out his turns, I'd be able to tell. He would play all of his cards at the start of each turn and rope me out. He didn't even win, and wasn't in a losing position until the end of the game, so it wasn't even out of salt.
I consider it wasting my time because it's factually what's happening. If you don't have any plays left, end your turn. Is there something I'm failing to consider that justifies doing that?