I always count on having to explain everything to my LBS. I'm not even sure the sales guys would know what a tubular is... they had a lot of trouble with the concept of "track cog" when I went in there last time. I like 'em fine, they're very nice and all, generally can at least order what I'm looking for, but I wouldn't take their advice on bicycles.
As to folks being nasty to retail employees, that's all too true. As if someone earning minimum wage is going to be inspired to learn much, if anything, about their job. And if they do choose to learn something about the job, chance are they're not going to last at it-- because they'll find a better gig.