The problem isn't even so much that the banlist is supposed to act as a guiding star to help players ban cards in their own playgroup, but rather the unpolished example is the rule of the land for sanctioned gameplay.The problem with EDH's banlist is that it's apparently supposed to be an example banlist, with the idea that your local playgroup would curate your own banlist over time as your local meta evolves. You're supposed to read the banlist, see that (for example) Upheaval is banned, and intuit that Cyclonic Rift should probably be banned as well.
The issues with this approach should be bleedingly obvious to anyone with eyes.
So even if your playgroup allows Sylvan Primordial (like any sane person would) and bans Cyclonic Rift, it doesn't matter because if you sit down at a Command Fest or something those cards will be banned and legal, respectively.