They're not geniuses (well, maybe they are who am I to judge?). It's just plain logic. One mitigating factor, though, is that if he had kept Kane on the bench and we had still lost the game - which was a very likely outcome considering Liverpool were the better team -, the backlash would have been unimaginable.
Not only would there be people, years and years later, saying he cost us the game by keeping our talismanic striker on the bench, but he would have gone down in history as the man who prevented arguably the best striker in our history to play in the most important game in the club's history.
After spending three months on the shelf, there was no way Kane could win the match on his own and that's what we needed on the night. Heart says 'play him', head says 'play a fit player instead' but head also says 'hum... what's going to happen if you don't play him? Let me think... Ok, let's play him!'
