Bullshit. It's not about banning pink for girls, but opposing morons who insist on making the association, who can't seem to get that pink as a symbol of femininity is cultural, transient, and arbitrary in meaning, and who expect and even demand that everyone follow along with it or else, as if it's a moral issue, while completely oblivious to the actual moral issues of human rights.
		
		
	 
Not sure I follow.  Are you saying the problem is the toy companies, girls clothing companies, etc are somehow demanding that girls (or their parents) buy their pink products?  The consumer can always say no, and if enough do, the companies will start losing money and come up with something else.
		
 
		
	 
No. The toy and clothing companies are following the culturally manufactured dictate that "pink means girl", and making a huge % of their products pink, and at least in pink packaging. They create ads that run during cartoons where the girls are wearing pink and playing with pink toys in pink rooms. 
Little girls want what is in the the "girls" aisle at the toy and clothing stores and what they see girls wearing in the commercials, and thus they want pink. And it starts before then too. Before the kid is born, the parents get gifts for their upcoming "girl" that are pink, pink, and pink. Part of that is family and friends who buy into the "Pink means girl" mantra, but part is because those who do not give it any thought are highly likely to buy something pink just because they went to the "girls" aisle and that's all they had. 
The product makers and advertisers are not the originators of the idea, but they make it impossible for any parent in the US to raise a boy or a girl without that association being formed by the time the kid is old enough to even point at what they want, and it gets stronger everyday. While so much pink is nauseating, that isn't really the problem. The total cultural dominance of the pink association is more a symptom of the real problem, which is the cultural dominance of strict gender roles about every aspect of life that are also drilled into everyone from the womb.
I recently had an vivid experience highlighting this issue. I wanted to buy some plain 1 year and 3 year toddler t-shirts so I could iron-on some patches from a local brewpub that is the only restaurant my friends two little girls had ever been to. The 3 year old calls it "The restaurant", and she associate with me because I often meet them there for dinner. 
I could not find hardly any 1 or 3 year old t-shirts in the girls section that were just plain of any color. Almost everything had flowers on it. The few things that were plain were hot pink or really bright florescent hues of other colors, which clashed with black and the earth-tone colors in the patch. There was nothing grey or any earth-tone brown or green. So, I bought plain grey shirts in the "boys" section which were easy to find. 
BTW, the kids and their parents loved them. 
Getting back to the march: Yeah, whether intended or not, they reinforced the stereotype and strengthened the "pink means girl" association in the minds of every kid they saw it. Any other more complex political message isn't going to change the fact that every kid interpreted it as "They are wearing pink, because its by and about women."  Besides, few marchers had a more complex intended message behind the pink beyond using its association with females to show unified support of females. 
But again, that association isn't really the problem, just a symptom. So, using it in the service of fighting against very real problems women face does more good than harm (even if some of those problems are partly due to gender role presumptions that the pink association is symptomatic of).