Legal term meaning that discrimination on that basis is restricted. In the context of employment law, it means that you can't, for example, fire someone for being a racial minority. The question here is whether the same analysis applies to firing people for being gay.
His lawsuit has the following allegations:
1.) He received good performance evaluation
2.) He came out as LGBT at work through his participation in a "gay" softball league
3.) Shortly thereafter he started getting pushback from certain managers.
4.) They then conducted an audit and fired him.
His argument is that title vii prohibits firing people in a protected class, LGBT is such a class, he was fired for being gay, and the audit was pretextual.
Their argument is that 1.) LGBT is not a protected class and 2.) even if it was, the audit was the actual reason that he was fired.
The 11th circuit agreed with the first issue. Other courts have held differently.