YABU.
Children learn through play and what they should learn is not that certain kinds of activity are off limits to them because they are a boy or a girl.
The trouble with saying 'parents can choose' is that our choices are narrowing all the time. I'm as old as Moses and remember that many, if not most, of the toys I played with with my brothers were gender neutral. That's really not the case now. and it becomes self-perpetuating: if my daughters are going to a birthday party I usually do end up buying something pink and sparkly purely because to buy, say, a Meccano set would be seen as Making a Big Grim Feminist Statement.
I have one daughter who has always enjoyed the whole range of toys - dinosaurs, trucks, My Little Pony, trains, Peppa Pig - and the other who is obsessed with pink, make-up, dolls, party shoes, dresses, princesses. She has always been much more receptive than her sister on the 'right' way of doing things and she has absolutely picked up on every gender cue going. It is, of course, her choice (though I do secretly think it's a bit of a shame to get through childhood without learning ANY dinosaur names or even once playing with a train set) and innocuous in itself. But what happens when she enters the pre-teen phase and translating it into a narrowly defined image of adult femininity?
Incidentally, she has also shed many tears over the last couple of years about not being blonde. Because it's not just about pink, it's about the overwhelming association of blonde with pretty, feminine and good. (My daughter is brown-skinned.) Now, that gets me STEAMING - and don't anybody tell me it's not important. My daughter's tears show it is.