Indy, RUN do not walk away from that idiot. I don't deal with anyone who starts spouting this stuff in such a situation - even if you hadn't already ordered the wheels. Sales people who tell you what you should do without asking what you want the wheels for first are just jerks.
Chris King is getting some bad rap lately because they're considered too expensive for what you get. They have assumed the unwarranted cult status of a Mercedes in a field of many other equivalent level hubs and price themselves accordingly. Maintenance is stupid - they require special tools to maintain and CK controls the distribution, sale and pricing of his hibs. The bike shop has no say in the matter. Besides, the noise of a CK hub would drive you bonkers over time. Bubba has them on his mtb and they drive us all nuts.
Our LBS was actually quite happy that we went with WI over CK. Campy Record have a good reputation and they are what they are, but if they aren't available in a 24 spoke why go with it? Why build a $500 set of wheels on a set of outdated hubs even if you could find them tucked away in some dusty warehouse corner.
The guy obviously didn't get that pre-built wheels usually don't work well for someone of your weight. I can go on and on.
Basically, you said exactly what I've been saying over the years. Down to the LBS guys liking your willingness to research and come prepared with knowledge.
On the fit story for your friend, I hope she lucks out. You know what was lacking in that effort, or lack there of.
You did good and showed that you were obviously the more knowledgeable of the two. Besides, in the single speed crowd, WI hubs are considered the cream of the crop and while CK is trying to break into that market, the crowd is laughing at him for the exorbitant cost with no discernible improvement in quality or functionality. It's a market that tends to be critical of what my DH just called "rhinestone studded BS."
So, don't worry. You can justifiably be angry. Go have some chocolate and feel superior.
I think mimi nailed the guy pretty well.
Frends know gud humors when dey is hear it. ~ Da Crockydiles of ZZE.