For me its all about intent.
If he is genuinely trying to win the ball, then for me its a yellow. I still think Stephens at Cardiff was a yellow and Stephens at Boro wasn't even a foul, but even if you accept that Stephens should have got a red at Cardiff I still think Mounie's was a yellow. Ditto Balogun's challenge later
If he deliberately thought he's just leave his foot in and catch Bissouma, then its a red all day long.
My suspicion is that Oliver has called the second one and done him on a nasty piece of gamesmanship. My feeling from Mounie's less than overt protests is that he knows he's bang to rights.
'Lack of intent' was how Shearer got away with elbowing every number 4 and 3 in the league in the face week after week with no come-uppance. You can't referee a game based on suppositions about motive. Personally I think that if you go in studs up it should be a straight red even if no contact is made. Just as I think that if I get stopped in my car and am twice over the limit I should be banned - regardless of whether I have been driving carefully or whether I have wrecklessly mown down some kiddies.
I really don't understand what passes as thought process among some folks. Sorry if that sounds a bit rude - it was unintentional, so....