I know this is just person experience, but many of the people/organizations I follow on Facebook have posts that are often quite filled with people who disagree with them, explained in rational and professional courtesy. I don't personally experience this mob of group think, but I see popular/unpopular ideas espoused and their weakinessness explored in the comments (not without the internet's normal levels of trolling and batshittery of course).

Of course I curate who I follow often based on the courteousness of their followers - so self-selection and all that.