I have similar complaints with employees at Hancock Fabrics. I've learned a long time ago that just because someone works in a fabric store like that does NOT mean they have sewing expertise.
I limit my inquiries to pleasantries and ask the employees the sorts of things they make. Surprisingly, some of them don't sew at all and not even interested.
My mom is the best source of "know-how." Then I can find a wealth of knowledge here at this forum too.