As someone who has met or chatted with multiple female lers/lees, I can give my two cents.
1) Most don't actually post/try to have a huge presence on here because of how your average group of guys will PM flood the girl's box. Hell, the way I met my main 'ler is that she simply PMed me out of the blue because she liked a post I made.
2) A large majority of posts from guys/couples looking for a 'ler/'lee come off as sounding so desperate or not at all caring or implying they're basically requesting a service ("Hi, I'm a 22 m lee, ticklish feet, looking for female ler. PM me" or "I really neeeeeed someone to tickle meeee!").
3) If you're looking for a female ler, you will have a much better time just... dating. Lots of girls would love the idea of tying down the person they're dating, and if tickling is something that'll make them happy, they're pretty happy to do it considering it doesn't exactly take a whole lot of effort on their part.