The point of INS classic (which has been renamed Ins Redeployment) is to bring the game to the newest source engine. The current version in which we are playing is no longer in development.
So basically people working on the open source code are just trying to bring the game back to life even though it's not dead (dev team is dead but not player base). So no one in the community playing the game even wants to think about the old dev team anymore everyone just wants to play and updated version of Insurgency. You lost me with the "fork" part I'm not sure where you're going with that statement because all I can think of is, your asking why make the same game over on another engine? Answer is already stated above but look at this dod,cs,tf turned into dod:s,tf2,cs:s =)
