This is a ridiculous restriction.  We are already paying for Private repos, and all I want to do is  make sure one of my contractors doesn’t accidentally mark a repo as public.  

I agree this is ridiculous.  If you are paying for private repos, you should be able to ensure no one makes a mistake and changes a repo to be public!  This is not an “enterprise” feature, it is a normal feature.

Source for the policy:

To allow members to create private repositories only, your organization must use GitHub Enterprise Cloud. For more information, see “About repository visibility.”

I agree this seems an excessive restriction, and common use case for non-enterprise users to not want to allow their employees/contractors to inadvertantly make a repo public and leak data/code.

What is the best forum to respectfully request this feature be unlocked for GitHub Team customers?

It’s not Enterprise feature, you can change it in your Organization settings at /organizations/[ORG]/settings/member_privileges

Repository forking: Allow forking of private repositories

If enabled, forking is allowed on private and public repositories. If disabled, forking is only allowed on public repositories. This setting is also configurable per-repository.

Maybe I am missing something. But what does forking have to do with new repository creation?