Perhaps this should be made more clear when you sign up then? There was no indication that this would be the case.
There was no indication that rubbish would be necessary either. Somehow, most people make an assumption that they should post rubbish rather than making an assumption that they should make intelligent useful posts. The rewarding of intelligent posts isn't really a rule or forum policy, it seems to be more something that some moderators just happen to do sometimes when they feel like it. Probably the assumption is that intelligent people will post intelligent things, so there is no need to tell them to do so. Others are going to post rubbish regardless of what you "tell them to do".
Even so, if you read through the threads that are linked in the "NEWBIE README" pinned to the top of the Newbie Forum (seems like a good use of the 4 hours of Newbie Jail time), you'll find that in one of those linked threads a Moderator has posted:
Additionally the Administrator has posted the following in another thread linked in the "NEWBIE README":
If you have really good posts, you can post a request for preemptive whitelisting in the appropriate topic.
- snip -
When you sign up, it does specifically state: