The problem with this line of thinking, if you're equating pinball opinions to not understanding rocket science as a reason to keep quiet about a topic, then you're saying people that are voicing their opinions on a pinball forum don't understand pinball overall. I'm going to go out on a limb and say most people posting on a pinball forum have a general knowledge of pinball thus are qualified to make whatever opinion on how they feel about a particular machine.

I don't have a problem with people forming an opinion about a game they haven't played. It doesn't affect my view of a game. I personally need to play it to form my own opinion, but know enough about my personal preferences and play style to understand what playfield layouts appeal most to me and which ones are duds without playing them. Some people's minds are set and their opinions will reflect this. I'll still give a pin a chance though before forming my final opinion.