I am less moved by the argument that the Fearless Girl is an advertisement as I am by the argument that this artwork changes the meaning of another. The statue is great, the positioning is amazing, the two pieces work together so powerfully to deliver an important message. But that's also the problem. It's would be the same if another artist added to the bull statue so that someone was riding it. The two pieces together are now essentially one work of art. I love the new artwork, but I would be pissed off too if I were Di Modica.
I have basically the opposite reaction. It really rubs me the wrong way when companies use any kind of political ideals, progressive or not, to promote themselves. On the other hand, I think the fact that a piece of art can be responded to and have its meaning changed is what makes it interesting. Of course, not being the artist himself, it's easy for me to say that.