My thought process is simple - there had been no indication to kick for posts, or other. The ball is live once kicked. It was not out of the question in the match for the White team to tap and go. Blue were primed to fly up if they did. Blue had clearly seen the ball being kicked. The player was clearly kicking the ball forward, not controlling it, or similar.
All players (kicker included) did not complain. And the later acts of the kicker, shows he realised it was his mistake. (and over here they are always complaining - so it shows they didn't consider this an error from me)
The difference to the line out above, there is no ploy of the opposition. It is solely down to the act of the team with the ball. In fact the kicking team is posing unnecessary questions to the defence - was it tapped, was it not, can we go etc. When the reality is simple - was the ball kicked? Yes - than the PK has been taken. And if a team is not smart enough to realise that kicking the ball, means they have taken the PK, then they need to learn fast.
I am there to facilitate a game. A Penalty kick was given. The ball was kicked (Behind the mark etc, a noticeable distance). This way it is easy to be consistent. And what happens if next time he dribbles it to the mark, and then taps and goes?
I am happy with the decision (as were the players) - and would call it again. In the same way, that when a kicker come up to kick
and is dropping the ball and chipping it back to themselves, I consider that to be taking the kick.
(The playing keep up is another story from a different match - #10 walks up to the mark playing keep up, get flattened by the defence. He did complain, until I asked what he was doing when he was flattened, and the lightbulb went off in his head - he's not done that since. His coach called him all sorts of things, and agreed with me)