Much as I hate the play-acting, it's part of the game and, at the top level, you have to either deal with it or lose out.
The closest recent parallel that comes to mind is Son on Rudiger. Was the petulant little kick a dangerous assault? Nope. But was it retaliation and intent? Yep. Therefore I can't argue that Sonny shouldn't have been sent off under the current rules and guidelines.
Exactly the same for Martial and Lamela. It's something I hate about the modern game but, if you want to win, you've got to play smart.
It's not like Lamela went in hard to break someone's leg, for example.