discuss.answer
It's not just your install. Lack of a permission in a Resource Policy generally doesn't hide the option (though unchecked Administrator policy permissions generally do hide the options in the Top Menu).
The only way I know of to hide it would be to modify the core JS code, and that would hide it for everyone, regardless of any policy.
It might be possible to create some JavaScript to hide the button conditionally (and the option on the Resource Tree context menu), but it would be fairly tricky since they're placed there by JavaScript and you'd have to get your code to run after that happens, so the button would probably flash.
It might also be possible to hide the button, at least, with a Form Customization rule based on user group, but I don't think so.
