Not sure what L or any other rebbes were holding. Rav S didn’t sugarcoat jewish history and didn’t say that shoah is unexplainable, he just said that he can’t give a precise answer at this point.
Re: Moschiach, he relied on the gemora (where is it?) that if all t
ch of one generation will come together on the same street in yerushalaim, moschiach will come..