Like others I don't see the point in not being able to discuss plot points here. Is it more that you have concerns about questions about interpretation. If so, I have some sympathy with your concern, interpretation questions are unfortunately rather open ended for a QnA forum, but I still think it is fair game to ask them here.
You say that they are not questions to 'experts' - but someone may have watched Inception 20 times and read about it, who can provide more enlightened commentary about it than someone who has only just watched it once. For instance the Inception question raises the point about Cobb's Totem before he inherited his wife's - something that I had not considered before. The question is phrased in a very open manner rather than specifying some specific area of interpretation - but I don't overall the forum is better served with them than without.