How does the forward's foot catching the keeper's foot "force" his leg to be extended? Pressure from the forward's foot in that direction would be toward bending the knee, not extending the leg...or so it would seem from the video posted. Also, as to "going in hands first"...the keeper may have started his run with his hands extended, but he appears to have his feet ahead of his hands by the time he contacts the attacker.
I'm not an official; I've never taken the classes. I'm in no way an expert. My only point of reference is from observing over the years what (fairly) consistently gets called on the field. Don't think I'd go with the "last defender/scoring opportunity" scenario for a straight red, since the ball was already away on a missed shot when the contact was made. The scoring opportunity was already blown. Not even sure I'd go with the yellow since it may have been unintentional contact just from going out hard for the ball, unless there had been previous incidents and the card was issued for persistent infringement. I would go with calling a foul, because missing ball and hitting player, whether it is intentional or accidental, is still a foul. It happened, regardless of intent. An official cannot always accurately assess the intent of a player; he can only call based on the result of the player's actions. PK is justifiable.
It's interesting to see the criteria people use to argue with a controversial call. If they disagree with what the official thought was reasonable for the situation, they cite the immutable letter of the rulebook. If they disagree with the consequences laid out in the rulebook, they cry for "reasonable interpretation."
