You're missing how those trades went. Houston got rid of the salary they needed to in order to make the CP3 trade work, and since the Clippers were willing to take that on, they got some useful players and a pick. Denver was not willing to take on salary for Gallo, so Atlanta is the team that got the pick for being willing to take on the matching salary. Since Denver was only agreeing to do a favor by using Bird rights for a player they weren't resigning, they just got a 2nd.