1) I think it rather depends on whether you are simply not going out of your way to freeze terrible people, or whether you are actively trying to prevent their freezing.
2) Still don't see how current Kim rules in the future is any different from future Kim rules in the future Kim rules in the future. Also if North Korea is invaded by the UN/an FAI/whatever the dominant military power of the future is, then the invaders won't give a damn about North Korean laws.
This month's media thread includes a short article on some people's idea to have Ayn Rand frozen, which ultimately didn't happen. My first reaction was a shudder. I thought, I definitely wouldn't want Ayn Rand preserved forever. My second thought was, What right do I have to say who can and who can't get frozen?
Whatever your thoughts on Ayn Rand, I think this can spark an interesting conversation: What, if anything, should humankind do about people who are widely seen as harmful for the whole? For example, if the Castro dynasty in Cuba or the Kim dynasty in North Korea decide to freeze themselves to ensure they will continue oppressing their countries forever, should that be prevented? (And yes, my opinion of Ayn Rand is such that these examples came to mind.)