Right, but referees consider force when looking at danger and/or consequence. Which is why it was fine for that prick Bruno at Newcastle to whack Jorginho on the back of the head as long as he only used his forearm, and not his elbow.
The key for me is that he doesn't attack the ball and the player at the same time. He attacks the ball, and the opponent arrives and collides with him. Doku is stationary, and turning his body away from the swing of the foot. I think he has done enough to minimise the danger and is entitled to attempt to clear the ball. A big swing of the foot and/ or a follow through and yes, I would agree.
At the very least.... it is not a clear and obvious error. When I saw it live, and the pundits were oohing and aaaahing about how he was in so much trouble, my first instinct was that I would be stunned if VAR gave that.
The only downside is that if Liverpool lose the league by a point or two, we will still be hearing about it for the rest of our lives.