I understand your frustration at loosing students, but again, what I would call them is folks voting with their feet. I would hope we all could refrain from putting 'aikidoka' in quotes when refering to them (I don't know either side in this) because we've only heard one side of the story, and there is always at least one other side to hear. If you didn't charge them dues or mat fees, then yes, they were like someone you took in. If you charged, then they were like tenants who wanted to hang their most cherished family photo and you said no.
Not everyone is into self-defense, and it is no more your right to insist they be than my right to insist you stop. So don't worry about those who don't want to be in a self-defense oriented dojo, you will find others that do. Everyone has their own direction to find, and it wouldn't work if we were all trying to walk down the same street. I'm glad there are places for all of us.