@skilesare This change was made to help prevent malicious URLs from being in proposals, as they could potentially target NNS users who are logged in through the NNS Dapp.
The plan was to make governance proposals that could add a domain to the URL whitelist, but I think that another solution might be more useful, since as you point out, you can have ManageNeuron proposals that point to private URLs.
The URL field can be set to an empty string so hopefully this isn’t blocking you. And currently any URL can be added to the description field in markdown, so this particular mitigation is not achieving much in terms of adding security yet.
We are discussing other approaches. Sorry for the frustrating user experience.