Ok, after your clarifications: Yes, this does have a manipulative character to it. It just strikes me as a situation where the ideal honesty is simply not achievable. A group will have tacit beliefs and assumptions, there is nothing you can do about it. First come, first served. So better that you, with your rational beliefs make the case for something before someone else absent mindedly cites a cached thought created by their moralist/super irrational aunt 15 years ago, setting the moral ground into an awful downward spiral.

Also, my recommendation is to use this for beliefs in which you are the first one to believe something in a group (cryonics as a classic case), so frequently people don't even have prior believes about the matters at hand.

Finally, at an emotional level, maybe you can fathom what is it like to be 17 and different from everyone around you, think that reality is fundamentally different from what they think, and that life should be lived according to different principles than the ones that guide them, every single one of them. Every human being you have ever encountered. If you do, I think you know as well as I do how arrogance, specially in the form of disrespect for authority, may come in handy as a survival technique.
If you don't, take my word for it. Sometimes arrogance is not a weapon of choice, but a weapon of lack of choice.