Why do many (not all) non-Christians make inaccurate umptions w/o consenting a level headed professional?

Before I become slandered about Christians not being perfect either, or why are you so "woe is me"?, I just want to say that I want to be more informed, not slander anyone else. I am willing to listen before I make umptions, so I would appreciate it if you would consider doing so too. BTW, by level headed professional, I mean someone who interprets biblical text accurately, and understands the views of both sides.