Especially not a dumb question if I read this right:
Instead of using the Cargo Transfer button
All I have to do is hit the Colonize button and even if I don’t specified a planet to colonize it will still give the, "Load Population" order.
Hence, the only reason to use the Cargo Transfer button is if I want to control the amount of population or if I want to load units.
Figure out something every day.

(somebody remind me how long I’ve been reading this forum)
Thanks guys and thanks for the question, you have just saved me at least 3 mouse clicks per colonizer.