If I find religious stuff in those, I take it out.

What'd you think they would be? B&N lite? People only lend or give books that they don't need to read again. You'll find that out

You got that right.

I use them to distribute my cookbooks.

Blech. That's awful. That is very much not what LFLs are for. I think if I ran one I'd be out there every day, weeding it like some kind of book garden.

I've seen a few of these in my area and wondered if there was some organization behind them.

It's an interesting problem and I think the consensus of just recycling crap people leave in there, is the best method.

Personally I don't really care about this because I went over to the Dark Side several years ago and never buy a paper book unless it's one I really care about and it's not available in e-book form (an intersection that seldom happens). When I travel for business or pleasure I have my entire library with me on my iPad, all searchable and largely sharable as well.