of course if you get caught participating in a terrorist group while abroad, you may get your citizenship stripped for free. I think that I saw that suggestion on Reddit once
As I understand it, the prevailing precedent of the Supreme Court is that revoking citizenship is something that a person must willfully do with the intention of having their citizenship revoked. This wasn't always the case, as it used to be that Congress could declare revoking actions that applied even without intent. So it's possible that this could change, but it's been the case for over half a century and unlikely to change anytime soon.