From page 2: "Those who adopted the Civil Rights Act might not have anticipated their work would lead to this particular result. Likely, they weren’t thinking about many of the Act’s consequences that have become apparent over the years, including its prohibition against discrimination on the basis of motherhood or its ban on the sexual harassment of male employees. But the limits of the drafters’ imagination supply no reason to ignore the law’s demands."
Then later, on page 4:
"The employers also stress that homosexuality and transgender status are distinct concepts from sex, and that if Congress wanted to address these matters in Title VII, it would have referenced them specifically. But when Congress chooses not to include any exceptions to a broad rule, this Court applies the broad rule."
The Majority refuses to limit the scope of Title VII simply because the drafters did not consider gay and trans workers when they made the law, and also penalizes those same drafters for not creating exceptions for individuals they lacked the imagination to think of to start with.