...I don't understand why someone would think to grasp the pen feed up, or sideways etc. It seemed obvious to me right from the beginning that the shiny metal nib should face upwards. Any other configuration looks strange!
You make the faulty assumption that these people are thinking and looking. People who have never used a fountain pen, and have used a ballpoint pen their entire lives as a habit don't look at the point of the pen. Why would they? It doesn't change anything about a ballpoint's performance. I recently lent a fountain pen to someone and watched him use it. He was so focused on what he was writing (not in his native language, so it took greater concentration) he didn't notice that the nib was all catty-wumpus.
If you do loan someone a fountain pen, it's only fair to announce that that's what it is. There are lots of proper responses, but perhaps the most endearing is, "How do I use it? I don't want to damage it."