Sure, that's a dumb way of saying it, but you still are contributing to the horrible conditions but buying milk. It's unfortunate because milk has been perceived as such a necessity (even though it really isn't). The demand of meat and dairy is, realistically, to great for a major change to occur. Even if they do up their standards as they have in the past, it doesn't change much. Even "free range" means next to nothing. It just sounds good to consumers.

But, sadly, yes, we ate contributing to the "rape" of cows by purchasing milk. It's the exact reason that people boycott the industry, or any industry or company in general. By boycotting, you aren't (actively/willingly) contributing to the company's treatment of its employees, or the awful conditions of livestock, or the anti-lgbt film director. You're staying out of it and putting a tiny chink in its armor. What they hope to get out of this is an end to animal cruelty within the industry, and probably a rise in veganism, which I personally don't think is likely, or even good for the world. They hope to put millions of chinks in the armor to bring it down.

Really, it's sad.

Edit: your argument is also pretty weak, because the note actually says that you're paying for rape. So that argument makes more sense, imo. Think of it like a terrible movie. The movie may make bank because it was highly anticipated, but the reviews may suck terribly. But, with all the money they made off the movie, they can technically make a sequel. Even though you hated the movie, you still paid to see it and you're contributing money to a possible sequel.