Have those of you who think the OP is overreacting ever been into an Entertainer toy shop? In our local one, the pink Girls section contains all the dolls, stuff like Sylvanian families and all the household pretend play stuff - kitchens, ironing boards, brooms, kettles - the lot. The boys section has pretty much everything else, including all the construction sets (presumably apart from Lego Friends - I haven't been in since that was introduced this year). Arts and Crafts and Pre-school toys (which would include Duplo I suppose) aren't divided by sex, although that is a bit of an arbitrary decision since dolls etc, particularly the baby ones, would surely fall into the pre-school category just as much as anything else.
It is nonsense to suggest that boys and girl will cross the divide and pick toys from the other section - they know the whole "pink for girls"/"blue for boys" from a very early age and boys, particularly, will stick to it for fear of being thought girly. Also many adults buying for children will just head to the relevant section, not wanting to pick a "boys toy" for a girl or vice versa.
Anyway, surely it would make more sense to divide the toys by type - Kitchen and laundry/Shopping/Construction/Dolls/Action Figures/Board Games/Outdoor etc, just as they already do for some categories. That would make it a lot easier to find what you are looking for than having to guess whether a particular toy is more of a "boy" or "girl" toy in someone else's eyes.
And, yes, this applies just as much to any shop which has massive blue and pink signs up marked "BOYS TOYS" and "GIRLS TOYS"