Also, In the article I believe the reasoning is outlined that given you wouldn't fire a woman for dating a man, then firing a man for dating a man is discrimina

Also, In the article I believe the reasoning is outlined that given you wouldn't fire a woman for dating a man, then firing a man for dating a man is discriminating on he basis of sex. The behavior alone isn't objectionable, it's only when sex comes into play that you start discriminating which cases are ok and which aren't.