Why do I need 5 rep to post there?
Your reputation on meta is the same as your reputation on the parent site.
You can always read meta with no rep at all.
Because we allow anonymous participation, we require a small bit of parent site reputation to prevent spam, and ensure that meta is for active, engaged members of the community.
But if I've understood it correctly, this isn't correct - at least not the part about "is the same as your reputation on the parent site". You can link link your accounts, but they still have separate reputation scores, right?