Why shouldn't it? It did in fact, and there's really nothing anyone can do about it.
If Joe Dumars had picked Carmelo (well maybe not Melo), Bosh, or Wade, he would almost certainly have more than one ring as a GM. But he has only one, and thus, his legacy is less than what it might have been. Hell, he may have won another title with even Kaman, Ford, West, Outlaw, Barbosa, or Howard.
Nobody cares if you blow a low pick. People may have even forgot that the Raptors blew a lottery pick on Rafa Araujo. But you blow a 1 or a 2, and it costs you big. People should remember it, and it DID lessen Dumars' legacy, whether it SHOULD or not.
By the way, it should. It's a No. 2 pick in the most loaded draft of the decade. DUH!