I strongly agree that diagnosis is problematic. This is especially weird when people can be forced to take a medication against their will based on that diagnosis. This is really fantastically intrusive and oppressive and etc.
Another problem with diagnosis: some illnesses haw a list of (say) 9 things, and the patient must match 5 of them for 6 months. So the patient is a good match of 3 and a weak match for 2 and a poor match for the other 4. But anyone seeing that patient will read the diagnosis and will apply all the criteria to everything the patient does. "You would say that. People with your diagnosis are {manipulative}" (even if the patient was a poor match for manipulative).
Another problem with diagnosis: some illnesses haw a list of (say) 9 things, and the patient must match 5 of them for 6 months. So the patient is a good match of 3 and a weak match for 2 and a poor match for the other 4. But anyone seeing that patient will read the diagnosis and will apply all the criteria to everything the patient does. "You would say that. People with your diagnosis are {manipulative}" (even if the patient was a poor match for manipulative).