No one can stop you from killing yourself if that’s what you choose to do. There’s no way that a person can’t do almost anything that they really want to do. What defines us is not what we can do, but what we choose to do.
The irony is that nobody can stop most crimes that are committed.
If I'm driving down the street and decide to run down a pedestrian in the road, there's little that can be done to stop me. I could even adopt the libertine attitude that this is a decision "between me and my God," BUT THIS ABILITY IS NOT A RIGHT.
The libertines seem unable to grasp the fact that abilities and desires are not rights.