For me there is way too much doubt on the Vardy challenge to make it a red. He might have meant it but I'd need to be at least 80 or 90% certain it was and I'm nowhere near that.
Can't really be compared to the Nketiah one, as for that he has consciously made a challenge that has ended up using excessive force and clearly endangered the opponent. I don't for a minute think there was any intent or malice in it, but he has made the decision to make that challenge and therefore has to face the consequences. Whereas Vardy has caught his opponent who is on the floor in the act of falling following a fair challenge, I respect the views of anyone who thinks he deliberately kicked him but I just can't be sure enough to take that view. It would also have been out of context with the game, there had been no warning signs before and nothing after, and had they been winding each other up you can be sure that Mustafi and probably his team mates would have been making more of it than they did.