Aaq everyone has bechira chofshis and many people did go off in lubavitch as well. However- lubavitch as a whole had the strength to uphold Yiddishkeit under the most adverse conditions. That was the point. Whereas the Alter Rebbe saw 100 years earlier that Chassidus hadn’t yet been given the chance to blossom and ingrain Yiddishkeit to such an extent.
As to your second post-historical context is everything… what applied then clearly doesn’t apply now bH