When I've read females post that they wanted to date but nothing serious I never thought it meant that they just wanted to sleep around with one night stands. I just assume that they were not looking for marriage or a long-term commitment. You know like go out with someone to a movie, hiking, or another shared interest they have.
That is exactly what I thought, too. There is a category for "one night stands" and it is entirely different. On another site they allow you to choose more than one intention, which also makes matching easier.
I must say though you're getting a lot more messages than I receive.
I do get a few messages here and there, but mostly just meet-me and visitors. I think I'd get more messages if there wasn't an age restriction on messaging.
I wish I could say it gets better, but I've not experienced it, yet. I think for a middle-aged man in a very conservative part of the country who just wants to find some fun women to hang out with and be social, online dating is just not the right option.