While I can only truly speak for myself, I feel like women are more picky than men because a lot of the time we want something more than a hot piece of ass to hang out with.
We want someone we can emotionally connect with, be attracted to, and perhaps even have a conversation with. There is no bigger turn-off than being seen only for tits and ass.
I do respond to the occasional message and I even send the initial message every once in awhile. The first message I opened was from a guy asking how my weekend was and about a few things that I mentioned in my profile. Whether it be from a dude catcalling us on the street, online dating, or in my twitter direct messages — it can get repetitive.
The right balance is paying attention to the text in our profile and coming up with a thoughtful, respectful message. I clicked on his profile and viewed his photos.