Any kick there is excessive force, as the force that should be used is zero given the keeper has the ball in his hands. I've said the same in the past when players have been sent off for fouls when the ball isn't playable, the expectation now at senior levels is red for that.
If you were waiting for a bus and someone came and did that to you would you think it was acceptable behaviour? I doubt anyone would, so why would anyone think it becomes acceptable on a football pitch?
Also, to reiterate what I said earlier, look at the reaction of the player. He knows he has been caught and walks without a peep, why should he be allowed to stay on when he has just walked up to someone and kicked them?