I think a lot of the frustration with the call was that it is often not given as a red within this league. We've seen many similar studs-up tackles that are only given as yellows.Seems like its an unpopular opinion here but that was another part of the problem... he started out one footed but finished going in 2 footed and opened his legs up, his legs then got wrapped around the player. That's a red card slide. Add to that that his studs were up. It was one of those grey area fouls were the rulebook says its a red, but sometimes the ref wont call it. I personally had no issue with the call, it was a silly reckless tackle on jacks part and he should have known better.
ETA: also a lot of people are saying that it wasnt intentional so it shouldnt be a red. It doesn't always have to be intentional for it to be a red card challenge. Could it have been a yellow, sure. But red wasnt a bad call. If it happened to one of our guys and they didnt give a red id be livid.
That said, I didn't necessarily disagree with the red card decision. But I definitely would have liked the ref to have consulted VAR on it.