Well I'm an ex Dealer Service manager and my feelings were pretty much close to yours.
If someone's vehicle was in the shop being repaired and the customer wanted to talk to the tech I had NO PROBLEM with that..But if it was just a phone call looking for repair type information we had 1 standard line. Sorry we cannot diagnosis problems over the phone..
No different than having a TV repair man,heating and Ac,plumber,electrician,,,,etc.etc..etc..tell you whats wrong with something without seeing it.
Would you call your doctor and expect a competent diagnosis without him/her examining you? Well I guess some would