Thought it had to be at least a sin bin, if the guy had tackled him legit and then held him down he would of been sin binned, but he can smack him high around the back of his head, concede the penalty, the defence gets sorted, and no card? It was a joke of a decision.

A match DVD, as produced for the Leeds game, would answer a few questions.

I rigidly stick to a calorie uncontrolled diet

He wasn't going to make the line. Still a red card.

From what I saw part of the reason he got hit was he seemed to have stopped running (out of gas) and was ducking down and trying to spin back in another direction. Correct decision by ref.

why red card?
Even had the Bradford payer laid on to slow the play the ball was not a professional foul as there was no support player there to take the ball should he have been able to play it at the normal speed. By the time any supporting attacking player would have got there then then enough of the Bradford defenders would have been in position to negate pro foul.
As for contact with the head, yes its the defenders responsibility to pull out if contact with head is going to be made, Thomas changed direction and fell over, no excuse for head shot, but any ref worth his salt as you put it would have made exactly the same decision.