I don't see any reason why newbies don't have to learn bbcodes at all. It's not that very important or crucial to learn but it is also helpful and making your post well organized. There are other things that newbies should learn. Every newbie must learn about the forum's rules and other features such as search feature.
I think most, if not all posters are more or less familiarized with the basics, such as bold, italics and the quote thingy. The moment they click on those formatting buttons, the codes are displayed so yeah, known by heart.