The word "touristy" has been around a long time, long before Instagram came around. Singling out Instagram is just another way to make the age-old complaints of tourism slightly less stale.
Sure, it might be the same complaint, but if the severity is 100x worse it holds more weight. And if Instagram is the main vehicle for this behavior, then it is a fair target of criticism.
For another example of the effects of smartphone-enabled-social-media, check out some youtube crowd shots from concerts before 2000 and ones from today. Obvious is emergence of masses of people looking through phones and holding up phones; a bit less obvious and a bit more worrisome is that folks seem generally less excited to be there.