To take this back to where it all started, "who said, 'don't bother testing patients,'" I think it comes down to this...
There is an expectation nowadays that medicine should have all the answers, and that there should be a test for everything. That there isn't is clear. And I can sort of see the point that endlessly testing for things for which there isn't a *definitive* test might be harmful.
However, some enterprising characters (who happen to be psychiatrists) have sought to capitalise on this by offering their own "solutions", and by categorising the whole field of conditions that medicine cannot explain (or more importantly, cannot effectively treat) they can ensure that their dying field is rejuvenated, particularly as increasing numbers of psychiatric disorders are explained by biological processes.
Personally, I think this is a misuse of their "talents", and that they should be focussing their efforts on helping people to live with chronic illnesses (and all the 'psychosocial' issues that entails) until such a time that a viable treatment comes along. They certainly should not be standing in the way of elucidating the causes or developing those treatments - but that's what they have ended up doing. And they need to understand that that's why so many of us are upset with them.