IMHO very strong statements are always wrong -> "Therefore, challenging conversations, that are personally useful, have always been limited to small groups of people.".
History seem contradict that and to demonstrate that the conservative, quiet "middle" is almost always wrong over time. The only people who are eventually "right" are invariably considered to have strong opinions and to be fringe by the "middle".
This is almost tautological. The "middle" is where we are right now and "more right" is, by definition, not where were are right now.
Then the issue is that you don't know which is which, a priori. Most strong statements end up false, eventually. The statements that eventually end up right may have been strong all along, but most of their strong cousins will eventually end up wrong instead. Consequently, the cautious approach is to be skeptical of strong statements, since they will likely turn out false.
(I'm also not sure that the initial assumption is actually true. There are tons of examples where the strong statements have not prevailed. Remember those saying Covid-19 is a killer virus, decimating billions? Or that it's no big deal? Turned out neither. It was bad, but not that bad.)
"Weak statements" have no inherently better Bayesian prior to being more true than "strong statements".