The trouble is that I don't believe Travis is talking about either of these. Rather that what he did was illegal, and so he should be in prison because that's what happens to people who do illegal things. He's not worrying about the legalities of the issue, just that the action was illegal.
However let's break it down. The first question is, should there even be a statue of limitations on Sexual abuse and assault, especially given that we know that it can take years, if not decades, for victims to come forward, be it due to fear of reprisals,of not being believed, or what it could do to their families. Should abuses be able to get away with things just because they managed to intimidate their victims well enough that they don't get accused in time?
If you were to support the view that there should be no time limit to sexual misconduct allegations, then the statement that "Moore should be in Jail" is not at all nonsense, but rather a statement of position against Statue of Limitations on Sex Crimes.
This seems to me to be quite a legitimate comment to make.