I don't think that's the argument the earlier post is making. They are arguing that you cannot be compelled to do something to save some else's life even if it won't harm you, and doubly so without due process.
However, I think viewing someone's body as their own property is a better way to frame this. If you decide a fetus is trespassing in your body, where should the state intervene? The state couldn't force you to harbor someone in your home during a winter storm, even if you left your door unlocked and kicking them out would surely result in them freezing to death. If you believe that a fetus has adverse rights against the body it's growing inside of, then you need to make that case.