...That's what was said about women marathoners.
And it takes them longer, so they should get paid more.
No, most men's five-setters aren't that great of matches, either. Usually the winner loses the next match. If it's a final, whatever. But I'm not into turning tennis into a sport of who is the fittest. Back when all matches were five sets, it was serve and volley on grass, and the points were really short. That is not at all how things are now. So honestly, I am for everyone playing best of three sets, unless it's Davis Cup or a Slam final, something with a defined end.
The only argument for equal pay that holds any water is revenue, which is what Djokovic said the other day. But really, why do the guys even care? It's two separate tours, and they DO get more money except at Grand Slams and a few coed events (such as Indian Wells, where this just happened. And where, by the way, the women's final was about 100x better than the men's).