I ride a fixed gear bike with fenders. This makes the mounting of the rear wheel a bit more sensitive to being mounted straight since it will otherwise rub against the fender.
shops never put the wheel on straight. they always pull back against the cog which ends up mounting the wheel at an angle.
aside from rubbing against my fenders, is this offensive for any other reason?
I don't really see what being a fg has to do with it. Someone with an engineering background or more common sense than I have can tell you the reasoning, but I'd say your wheel should be straight. Anyway, isn't a rubbing fender enough of a reason? Just get yourself an adjustable wrench and do it yourself.
Yes, your wheel should be straight, for a number of reasons. The number one takeaway here is: find a better shop and spread the word about the ones that actually return a customer bike with the wheel crooked. There are too many REALLY GOOD shops out there that deserve to flourish to have their sales/service dilluted by the availability of inept high school dropouts operating crappy shops.
I never learned to ride a bike. It is my deepest shame.
Two reasons I can think of to have your wheels straight:
1. Alignment of wheels affect handling - just as if your frame was crooked, having your wheel in crooked will make the bike track not-stright.
2. WHen clamped crookedly into parallel droputs or fork ends, the axle will be slightly twisted and this can either bend your axle or cause your bearings to wear out faster.
Tell the owner of the shop each time one of his employees does such shoddy work. If he is a good businessman he will take corrective action (such as asking his employees to pay attention to things they do not think are important). If he is a lazy or poor businessman he may tell you it does not matter or make some other excuse.
Everyone makes mistakes. THe true test is how we deal with the mistakes when brought to our attention.