So what is supposed to be wrong with saying that "The Celtics released David Lee"? Talk like this is certainly common in everyday speech, which does not mean it is scientifically valid, but does place the burden of proof on those who want to reject it.*
Furthermore, consider what happens in a case where common speech would say, "The Celtics release David Lee." A group of executives charged with running the team meet together in a room, or on a conference call. They discuss the situation with Lee, his production, the size of his contract, who they could replace him with, how his release might impact other players, and so on. Finally, a consensus is formed in the room: Yes, we should indeed release Lee. Someone with the authority to do so declares, "Johnson, schedule a meeting with Lee, and tell him we are letting him go."
Johnson schedules the meeting as tasked and tells Lee the bad news. The Boston Celtics, as an organization, have acted to terminate their business relationship with one of their players, and we quite accurately say "The Celtics have released David Lee."
But imagine that during the meeting, Lee becomes agitated and hostile, and, as a result, Johnson socks him in the mouth. In that case, no one would say, "The Boston Celtics punched David Lee in the mouth." No, Johnson punched David Lee in the mouth: he was acting quite on his own, and not as a representative of the organization.
This difference in usage shows that in the first example saying a group acted captures a very important distinction in human social life in a succinct manner, and that demands by methodological individualists that we stop making this important distinction are akin to someone demanding that we stop talking about basketballs going through the hoop or bouncing on the court, and only speak in terms of sub-atomic particles re-locating in space.
* Common sense must be mostly right, or human beings would not have lasted 100,000 years on the planet. And the fact that everyone who wants to deny this points to the same two or three cases ("But, but, the earth moves!") is actually evidence for common sense: in the many millennia of human existence, these critics can only come up with a few notable cases where our common sense was spectacularly wrong.