Well, no. I'm FB friends with my younger brothers. The youngest is in high school, and has the sense of humor one expects to find in bright, 16 year old boys... rather juvenile. I'm not going to de-friend my brother. I work at helping to teach him what's appropriate and what's inappropriate, but of course that's not always successful. If he were to add me to some group because of some childish whim of his, that doesn't mean he's not my friend... just that he's exercised some bad judgment.
Do you immediately ditch all your friends the instant they do something against your wishes? If so, I doubt you have many left. Most of us have at least a few friends who on occasion act a bit like an asshole, but are our friends nevertheless.
The REAL problem here is Facebook failing to let its users have control over what other users do to an aspect of our account. I can un-tag myself from pictures. I can turn off the ability of others to tag me in photos. Why can't I turn off the ability of other users to tag me in (i.e., make me a "member" of) groups? I should have complete control over all aspects of where my FB identity is linked in FB.