Yes there are reasons,
Usually we dont like to allow new players into existing games because they either do undesireable things (in most cases start random dow-athons, liberations movements or do silly attacks that cost one side or the other too much for a game most of us invest alot of time into.
As with 99.9% of them they dissapear after 1 or 2 session never to reappear, and in some cases doing none of the things there Alliance leader requests.
We always post when were starting a new game, keep alook out and post when we do.
IF you play weekends then saturday after 1am is good time for random/throw together games. You must understand that some of us have been here for years and are just tired of seeing new players pop up every so often only to leave after theyve decided they have had enough.
If your face is still around 6months down the track you will find most people will be generally more appreciative that you are a reliable and regular player.
Just saying.