Was a penalty, there was no doubt about contact from behind so even if he’d also played the ball penalty would be right.
and if you are adjudged to have taken down an opposing player as they stand in front of an open goal, that has to be red, no?
No, as I said there’s now a double jeopardy rule. Has been in place for a while now. About 2/3 of the way down https://www.theifab.com/laws/latest/fouls-and-misconduct/#disciplinary-action
A genuine attempt to play the ball but that results in denial of a goal scoring opportunity (DOGSO) is not automatically a red card.
If it’s outside of the box then DOGSO takes preference and it’s a freekick and a red card
If it’s inside the box the penalty is the sanction. To also send off was felt to be punishing twice for the same offence.
If the offence itself is worthy of a red card then you can still get both (serious foul play like last night, double footed lunge), or if the offence is deliberate like a goal-line handball or holding, rather than genuine footballing mistake like a mistimed tackle, then it is still a red card.