Can an employer discriminate in severance situation for being a great employee?

A voluntary severance opportunity has become available where I work, and once I heard it was coming I decided I wanted to apply for it. However, upon receiving the HR letter that was broadly distributed, one of the exceptions is that if you were a top rated employee last year, you are ineligible to apply which feels like reverse discrimination to me. I am curious to know if there is any recourse or help available in this situation? I definitely don't want to make waves as I have the utmost respect and appreciation for my employer. This is also why I was surprised and disappointed to see that they did not extend the same courtesy to this group of people. This has not been an exception in past situations, so I was in shock when I read it (to put it mildly). Personally, I feel like I should have the same opportunity as others to leave with the same benefit as I've worked extremely hard over several years. Thanks in advance.