I don't think I have anything to add to what my friend said. In my view, the arbitrariness is based upon the facts that were pointed out. It will be difficult for people in advance to anticipate whether they fall within it or not. It will be difficult for the courts to determine actually whether they fall into it or not. The process is also arbitrary.
Someone asked about the right of appeal. The difficulty we have is that there is no set right of appeal, so presumably the only right would be a right of judicial review at the end of the determination by the citizenship judge, without any right to a hearing. A process that has such serious consequences, which doesn't provide for due process and doesn't provide adequate review mechanisms, is hugely problematic and could be considered arbitrary on those points as well.