First doc sounds like a misunderstanding. Never seen any guidance remotely like that. Second doc is giving the standard easy-way-out guidance for people who won't quarantine. Third doc is following actual CDC guidelines.
The vast majority of doctors, including those in political positions, agree on the correct course of action. However, they are dealing with people who won't follow the actual protocol, so they try to tweak it to get as much compliance as possible. As a community, we have experience with different rabbonim giving different heterim depending on who they are and who they are talking to. We take our Judaism more seriously than we take science, so while we scoff at those who shop for the most convenient heter, we don't think twice about shopping for the most lenient way out of quarantine. Given what the doctors are working with (in terms of people looking for protocols), it's not surprising in the least that their guidance is all over the place. What is surprising is people deciding that since the guidance is not uniform, it must all be fake and we shouldn't listen to doctors anymore. If someone made the same argument about Judaism, we'd think they were ridiculous.