I'd love to see data behind this question, but yes I believe that there is significant variation in the required intelligence to perform the highly various professions that the human race engages in. And I would claim – in all the humility I can muster speaking as a programmer myself – that the average programming job does inherently have a higher bar for intelligence than the average other profession.
It would be very wrong indeed to extrapolate from this information that one should TREAT individuals differently based on their choice of profession! Even if we knew for certain that the Brick Laying profession only consisted of the 1% most intelligent individuals and Data Entry Specialists the lowest 1%, treating individuals with these professions differently from a policy or cultural perspective would, in my opinion, be a great injustice.