[em-bee]

i don't know if understand you right, especially i don't get how hedging is manipulative, but here is my take:

this applies in particular to pseudonymous written discussions like hacker news. i don't know who you are, and i don't know your character, but if i read you hedging your statements instead of speaking with authority then that gives me the feeling that i can have a constructive conversation with you even if i disagree with what you say. it doesn't mean you have to hedge everything, but that you indicate about which things you are more sure about and about which you aren't.

whereas if you write in an authoritative tone then i can either try to find out who you are and verify that you are indeed an authority on this subject, or i can blindly believe you (which i would only do if what you say confirms what i want to believe as true for myself) or reject you as someone who is unlikely to be able to reason with and give up responding. neither of which is a good choice. at best i can give a hedged response that explains why i believe i am right to disagree and hope that you are able to explain to me why you should be right after all. this is where not being afraid to be wrong comes in for me.

and once we enter a state where we both have opinions that we are not certain about we can then continue to explore the subject matter together until we can find a consensus that we both can agree with.

and it may just be that one or both of us changed their opinion on a subject completely because in the course of our exploration we both learned something new. but that is only possible if neither of us act like an authority on the subject refusing to accept new input.