On the other hand, you can only be considered a threat as a consequence of specific actions you took in the past.
When you get out of prison that means that, according to the law, you're no longer a threat, and there shouldn't be any reason or justification for limiting your freedom or shaming you publicly by putting your name on a list.
While I can't speak of US law, being on probation in Sweden is just an other name for a shortened sentence. The general idea is that you spend a portion of the prison time outside, but under strict conditions.