Good point. I think people may confuse logic with believability.

I could propose in this comment a cure for cancer based on a perfectly sound a logical argument and my (lack of medical) credibility would have zero affect on the cogency of what I was saying.

But it does mean, you should probably not be convinced, or at least not send me all of your money to invest in my cancer research startup.

Also for some reason it's very easy to judge something as reasonable when we actually don't have any domain expertise. Not sure why, it seems built into most of us to feel natural.