There are two ways such an argument could go. One is that not-thawing is punishment. He was a bad guy and wasn't punished enough during his lifetime, so now we will punish him more by not thawing him. That argument, as you imagine, has some problems.
I can think of two situations where you might want to do this:
The punishment consisted of execution
Followed by cryopreservation?? 8-0
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.)