Suppose you invite me into your house. After a cup of coffee and a nice conversation, I start doing things which you do not approve, e.g. making prank calls from your land line. You demand me to stop and leave but I refuse and I keep going until I am completely satisfied.
I didn't force you to invite me into your house in any way. You did invite me under the impression that we would have a nice time, but then the reason for the visit changed, could cause you trouble and you felt uncomfortable, so you were within your rights as a citizen in asking me to leave. Me not complying constitutes assault and trespassing.