You can say whatever you like when you are jailed. But I have limited sympathy, which I reserve for true victims of circumstance. You (usually) knew it was illegal when you did it.

It's fine to disagree with the law, to protest it, to seek change. But "doing it anyway and hoping you don't get caught" is not an attempt at civil reform.

BUT you do have a right to object to unreasonable punishment. That's absolutely within your rights. "His sentence is way too long for his crime" is a discussion I'm happy to have.