They seek to show that Proposition 8, like Colorado's Amendment 2, singles out a group of people for discrimination.
Justice Scalia tore the majority a new one in his dissent:
The Court has mistaken a Kulturkampf for a fit of spite. The constitutional amendment before us here is not the manifestation of a "`bare . . . desire to harm'" homosexuals, ante, at 13, but is rather a modest attempt by seemingly tolerant Coloradans to preserve traditional sexual mores against the efforts of a politically powerful minority to revise those mores through use of the laws. That objective, and the means chosen to achieve it, are not only unimpeachable under any constitutional doctrine hitherto pronounced (hence the opinion's heavy reliance upon principles of righteousness rather than judicial holdings); they have been specifically approved by the Congress of the United States and by this Court.
In holding that homosexuality cannot be singled out for disfavorable treatment, the Court contradicts a decision, unchallenged here, pronounced only 10 years ago, see Bowers v. Hardwick, 478 U.S. 186 (1986), and places the prestige of this institution behind the proposition that opposition to homosexuality is as reprehensible as racial or religious bias. Whether it is or not is precisely the cultural debate that gave rise to the Colorado constitutional amendment (and to the preferential laws against which the amendment was directed). Since the Constitution of the United States says nothing about this subject, it is left to be resolved by normal democratic means, including the democratic adoption of provisions in state constitutions. This Court has no business imposing upon all Americans the resolution favored by the elite class from which the Members of this institution are selected, pronouncing that "animosity" toward homosexuality, ante, at 13, is evil. I vigorously dissent.
Saying marriage is between a male and a female is not singling anyone out. People are usually male or female.
Ir's a matter of settled legal doctrine that the latter singles out a group of people for discrimination. How is the former different?