This is true, but not generationally. Rather, the younger someone is, the less they generally know, and the more.opinions can be shaped.

You're not wrong, but you're also wrong. :p

What I mean is that normally, youth is less "wise" than elders, because of how long they've been alive. The more mileage you put into Life the more you figure out. Its one of the great ironies of the human species that just as we finally start to get wise enough to figure out WTF is really going on, we drop dead. And even worse, trying to pass off some of that wisdom to the previous generation usually falls on deaf ears, because its seen as 'old person yells at clouds to get off of their lawn' by the younger generation.

Having said that, I'm still going to disagree with you in that the original comment is specificially (IMO) targeting the newest generations as specific entities onto themselves, and not just more youthful; the first post-new Internet generation, as being less informed/aware.

If you’re trying to have a social media presence you are de facto targeting a younger audience

One does not beget the other though, its just a coincidence. The 'de facto' is targeting the dummer/spends more crowd, not a specific age crowd. If older generations were 'dumb' and spent more, they would be the ones targeted.