I don't think Inquisitors are completely random.

It is not JUST your standing with the pope. If you do something like fail a pope mission, sack a catholic city, or generally have a province with high heresey the pope will send an inquisitor to deal with you.

You had probably done something to annoy the pope in some way.

Now if you think about it, perhaps the Pope did not want a man who lacked such devotion leading a crusade.. the Pope felt threatened that the crusade was more for personal gain of the King in question and would not benefit Christianity. ;)

I doubt the game is that smart, I think you just had absurd circumstances.