I think the point was that 'fashion' has never been a primary focus of the show that would warrant it being mentioned so prominently in an official description.
Yes, Rarity is a fashionista, but that was always balanced by the fact that AJ, RD, and Twi all seemed to be rather ambivalent to it.
It was a nice contrast to typical 'girl' advertizements where everyone is obsessed with looking pretty and Hasbro's wording seems to be taking a step back from that.
That's what the OP was complaining about.