These sorts of red cards always cause a debate like this because everyone who has ever played the game knows that they almost certainly would have done what Mane did. It wasn't in any way malicious, it was just unlucky and given the number of malicious tackles that don't get a red, one like that always gets a bit of sympathy. I remember enjoying tremendously the red card given to Nani (I think) thereby knocking ManU out of the CL in Ferguson's last season.

It was less of a red card but, like Mane's, a red card nonetheless.