Good points you make and I agree with the last two. However, (just cause I'm in a picky mood this morning), 'unconditional' love is unrealistic unless it is a parent's love for their child. It would mean "I love you no matter what you do." I don't even feel that way about Mr. Bee.
Certain 'conditions' are met when you decide that this is someone you want to be friends with, so if those 'conditions' are betrayed, I wouldn't necessarily expect that loyalty would continue. For example, finding out they are: a cheater, a thief, physically violent, dishonest, disloyal to you, etc.