If someone in your LBS doesn't know how to work on them its got nothing to do with being insensitive to 'old bikes', its just that they're generally ignorant/incompetant anyway.
Quite true, I just attended a cycle mechanics course and it covered the whole range of components...square taper, isis, HT2, GXP, BB30, canti's, v-brakes,discs etc etc... so really if someone is employed in a LBS as a mechanic they ideally should have the basic qualifications to do that job, and if they did then they'd have at least a basic understanding of "retro" parts. (although I will never forget going into a "respected" bike shop one time and asking for some cantilever brake pads..."are they for disc brakes?"
My LBS is actually rather good, they like to see the retrobikes for a change, it's always a good conversation starter, and they do actually know what they're talking about! I've built up a good relationship with them and quite often they'll turn my bike around in the workshop as a matter of urgency, or if I need a few bolts they'll just give them to me free of charge.
I remember not that long ago your LBS was a friendly place where you went to buy stuff, get stuff fixed, and chat about stuff, quite often people would just drop in for a chat... There are still some of these LBS's about, but more and more have either closed or turned into corporate mass-marketing machines