Watching it last night we all thought it looked a soft penalty at first but after they showed a replay from behind the goal you could see it was 100% a penalty.
That replay showed quite clearly the no 5's right knee hit Sterling as he was running and then the other defender took him out with a body check while Sterling was off balance from the initial contact. I was pretty hammered but don't remember it being shown more than once.
I can't quite believe this has been made out to be anything other than a 'stone waller'. Even in the video above you can see that one defender impedes his right leg and the other stops the movement of his left, all without touching the ball, how is that not a penalty? If either defender had tried to play the ball rather than the man then I could understand the 'soft' argument but they don't go anywhere near the ball.
Maybe if Sterling had stuck out his right leg to catch the defenders trailing leg a la Fernandes, Salah, Mane, Kane or Vardy it would have been talked of as 'clever play'.
It would be interesting to know whether the penalty was awarded against the number 5 or 24.