People drive dangerously and nothing happens to them either . Not every sakana ends in disaster and sometimes people lose zchoyus as the result of placing themselves in sakana.
שומר פתאים ה׳ according to some is only about a danger that isn’t apparent but known through statistical data. According to others it only applies to a danger that is COMMONLY ignored. Neither of them apply to traveling to enter a war zone. Even if that war zone is Uman.