Stop adding community neighbors who don't play
Usually I can only gift when I drop a neighbor, but they are still a facebook friend.
As for the inactive neighbors? I think this game is more interested in getting new and or old players to come back then making the current ones happy. Half the time I look for the neighbors that help me the most I can not get to their farms. Like you I can only get to the ones that have not been played in years with withered crops and old things on them.