When editing the developer portal user, under Audience>Accounts>Listing>Account>Users>Edit user (/buyers/accounts/{acc_id}/users/{user_id}/edit) there is a selector for the user role which shouldn't be displayed for developer portal user as they haven't roles.

Please see the comments in this issue and also this comment in related issue.

It is true that the radio button text on /admin/account/users/<userID>/edit should be changed to something more descriptive - something like what is in the screenshot above.