To offer this service, we (Coinbase) work with those bank rules and that is why you are seeing our service act much like the traditional financial world. You might not like this, but we didn't make those rules, and it is the only way I know of that works if you want to exchange bitcoin in the traditional financial world. (John's answer from the support thread you linked also explains this).
Accepting purely bitcoin-to-bitcoin payments would be one solution that might work for this if that is what you want (there are plenty of other solutions other than Coinbase for this). I should mention that we are probably at fault for marketing it more as a bitcoin wallet vs an exchange which has different implications to people (I think this is part of the reason for the confusion).
Finally, I believe you may be mistaken that you can't access the $5k in funds. Are you sure? This page describes our policy on that topic: https://support.coinbase.com/customer/portal/articles/190568...