Because you're friends. Why is that so absurd?
Personally, every once in a while I open my gate and WAIT for random people to come by. It's nice to keep in contact if you haven't had the chance to put them on your Best Friends List for example.
I didn't mean to be rude, but it's actually your fault if you're just too lazy to kick them off your list.
Also, if you dont want them to stay, simply tell them to leave.
you apparently can not read.
NO most people I add are NOT my friends...they are people I have done trades with or given stuff to.
I am NOT lazy, I just have a life and do not dedicate my entire life to a game, its a hassle, I have children and a house to take care of, and if I forget to delete someone, its not out of laziness.
and I also stated back there which you obviously ignored...4 different times i asked people to leave, and they refused, leaving me to have to switch it off...someone told me TO PAY them to leave once!!
good for you for letting people in your town, obviously u never had ur things stolen or destroyed. congrats.