Jack, 25, was shown his fourth red card of the season for a lunge on Aberdeen striker Stevie May, which referee Willie Collum deemed to be dangerous during the Gers' 2-1 win at Pittodrie.
Replays showed former Aberdeen ace Jack winning a 50-50 challenge after a heavy touch, but following through on May's ankle that saw the former Sheffield Wednesday striker come off worse.
Bett believes that Jack deserved to be shown red and does not agree with the club's decision to appeal the dismissal, despite Jack seeing two of his previous three red cards overturned by the Scottish Football Association.
“I think it was a pretty obvious red card,” Bett said. “He did get the ball first but his follow through looked pretty bad on the replay so I don’t think the referee had any choice but to give him a red card. He did get the ball first but it didn’t look good.
“I don’t know what Rangers are doing trying to get it overturned. It was a red card and that’s it. You could see it was a red card. The two of them went for the ball but Ryan caught him on the ankle. It didn’t look good.”
Rangers earned a second win over Aberdeen in the space of five days following Wednesday night's 3-0 win, with goals from Danny Wilson and Josh Windass enough to brush aside Derek McInnes' side.
Rangers' number eight Jack could now miss games against Ross County, Hibernian and St. Johnstone, if his appeal is unsuccessful.