They're all just words, right? For the same idea?
Not really. A co-op or exchange, is like the public option, except it is small enough and weak enough for the big insurers to kill. In 38 states, a single insurance firm dominates the insurance market with at least a third of the market in that state. If a public option is replaced by 50 dinky, weak state exchanges, the insurers will destroy them. And then go back to robbing us blind as they are now.