Rex Wockner notes that part of the Delhi decision is based on Jerry Brown's argument against Proposition 8:
In the present case, the two constitutional rights relied upon i.e. 'right to personal liberty' and 'right to equality' are fundamental human rights which belong to individuals simply by virtue of their humanity, independent of any utilitarian consideration. A Bill of Rights does not 'confer' fundamental human rights. It confirms their existence and accords them protection.
The opinion also holds that "sexual orientation is a ground analogous to sex and that discrimination on the basis of sexual orientation is not permitted[.]"
"But Maureen," you say, "that's great news for India, but what does that have to do with the US?" Simple. India and the United States are both common law countries - our court systems are based upon English courts. We were both British colonies; consequently much of our pre-Independence laws are based on the British law of the time. Furthermore, common law courts often look to decisions in common law courts in other countries when there's no applicable domestic precedent - not as binding precedent, of course, but rather as persuasive precedent. In fact, the High Court's opinion notes that previous decisions on Section 377 cited the Corpus Juris Secundum, one of the definitive restatements of American case law.
In short: The most influential appellate court in a) the world's largest democracy and b) the world's largest common law court system has declared that discrimination based on sexual orientation is impermissible.
Law dorks may read the entire opinion here.