I have been receiving complaints recently about some new members being bashed by older ones in their first posts.
don't go attacking newer members. Often they are genuinely looking for help. Giving an answer that is almost comparable to elitism won't help at all - I've seen some answers that are just outright insulting towards the new people on the forum. Behaviour such as this just drives them away, what's the point of being in a community who won't help newer people?
Should this be in the rules? Maybe, but there's already a warning to treat people nicely in there. This is a warning to specifically say, don't hate on newer members, often you'll know more than they do about MH, but don't go hating even if it is a somewhat stupid question. Leave a good first impression.