In my opinion there shouldn't be a height limit in the app. There are no laws or regulations on the books today limiting height, at least not in the US. If there were then that's another story and by all means throw whatever that limit is in as the max height.
It's weird that DJi picked 500m to begin with. You would think they would have gone with the 400ft limit instead as this is the guideline, not law, in the US. I believe that same guideline says to maintain Line of Sight yet there isn't a hard max distance limit at all.
Take the limit out and then put it back in if something becomes law. I would be the first to update my firmware to stay within the legal limit.