The biggest inactivity issues occurs from accounts joining in their first 2 weeks.
If a player is inactive in the first two weeks it usually means they stumbled across the game, didn't like it or even accidentally logged in from facebook, either way the game gets flooded with these pop up players (not to mention all the cheaters deliberately creating many, many accounts) and this floods a world with inactive chaff, which causes serious problems to the world capacity and activity/quality of play for actual players. And so yes, the activity rules are a little harsher at a player's start up, in an attempt to keep a fresh turn around on world start up.
Generally it takes a player 1 month to be listed as inactive, but if they are inactive within the first 2 weeks then they are listed early.
Otherwise the map would be flooded with inactive villages and "reseverved" spaces for the second village slot.