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.
The Gemara in Kesubos, (תניא הכל בידי שמים חוץ מצינים פחים, see tosfos amud beis) states that when one puts themselves into a dangerous situation, knowing that it is dangerous, they lose that protection. You need to be a bloody dingbat to even think about going, regardless of what happened last year..
If someone continues disreardging danger, he is either a rasha or, l’tzad zechus, a meshugene. The latter one is patur m’mitzvos, so he does not need to go anywhere for Rosh Hashona (other than his doctor).