[Hostile85]

The whole idea is so that you don't have people able to buy their way to the top in a short amount of time by purchasing implants then buying humanity to negate the disadvantages of implants. It's the same reason stat increases from implants don't count towards equipment.
The game favors activity and long term commitment. Donors have an advantage but it isn't overwhelming. Allowing people to donate their way to getting humanity back could become a huge (and unfair) advantage for some.