They did this. They said that. They want it.Not only is it poor grammar and syntax to refer to an abstract in such a fashion, but it's limiting in terms of ones ability to express and clear statement.
Is "they" big brother? Is "they" the government? Is "they" they people who do things? Is "they" a mad scientist? Is "they" an oompa-loompa?
By using "they" the speaker implies that he/she doesn't know what he/she is really talking about. There is, and always should be, a definable entity behind the reference to a "they" in conversation.
Maybe next year, I can try to give up "they" during lent.