Hi,
The solution is not very recommended but I think for DISPLAY, you can valueRule,
1. put a hidden field on the Entity Form and on load fill the field with the user ID (xrm.page.getUserId())
2. In display rule use value rule if the field value matches your specific user id value don't display.
Another solutiion can be Enable rule, use CustomRule
1. Create a webresource/javascript function and return true if user matches.
see the CRM SDK for details search for 'Define Ribbon Enable Rules'
Cheers,
Hassan