That is not my reading of it

>In Lawrence the Court acknowledged the interlocking nature of these constitutional safeguards in the context of the legal treatment of gays and lesbians. See 539 U. S., at 575. Although Lawrence elaborated its holding under the Due Process Clause, it acknow ledged, and sought to rem- edy, the continuing inequality that resulted from laws making intimacy in the lives of gays and lesbians a crime against the State. See ibid. Lawrence therefore drew upon principles of liberty and equality to define and pro - tect the rights of gays and lesbians, holding the State “cannot demean their existence or control their destiny by making their private sexual conduct a crime.” Id. , at 578. This dynamic also applies to same-sex marriage. It is now clear that the challenged laws burden the liberty of same-sex couples, and it must be further acknowledged that they abridge central precepts of equality. Here the marriage laws enforced by the respondents are in essence unequal: same-sex couples are denied all the benefits afforded to opposite-sex couples and are barred from exer - cising a fundamental right. Especially against a long history of disapproval of their relationships, this denial to same-sex couples of the right to marry works a grave and continuing harm. The imposition of this disability on gays and lesbians serves to disrespect and subordinate them. And the Equal Protection Clause, like the Due Process Clause, prohibits this unjustified infringement of the fundamental right to marry. See, e.g., Zablocki , supra , at 383–388; Skinner , 316 U. S., at 541

That last sentence is the key:

>And the Equal Protection Clause, like the Due Process Clause, prohibits this unjustified infringement of the fundamental right to marry.

They are not "magically" combining anything. Disallowing gays to marry is a violation of BOTH the Equal Protection Clause and the Due Process Clause.

This is where they simply assert there is an equal protection clause violation based on the fact that there is a substantive due process violation. It's just assertion. There is no precedent they are drawing on, and in fact, they acknowledge Lawrence was not an equal protection clause win. In fact, it was an equal protection clause loss, as i cited.

They point out a bunch of things about substantive due process (not equal protection) Then, they simply assert ">And the Equal Protection Clause, like the Due Process Clause, prohibits this unjustified infringement of the fundamental right to marry." This is not a legal argument, it's, as scalia would say, jiggery puffery. It's not a citation of precedent. It's not a logical argumentation from the standards applied to equal protection claims. You can see there are zero tests being applied here. It is simply bare assertion.

Basically, nowhere in this paragraph, have they explained how it is an equal protection clause violation for legal reasons. They just assert it exists.

There are in fact, reasonable arguments and conclusions to be made on either side of this particular legal battle. The majority made none of them :)

(As i pointed out, they could have held this was sex based discrimination subject to heightened scrutiny under the EPC, and disallow it there)

To be honest, if we are going to play armchair lawyer on hacker news, suggest you read these, and the decisions they refer to, with a really critical eye (to both sides). I suggest you take the time to look at what law schools outlines teach (it's a fine source if you want crib notes) about the equal protection clause.

With no disrespect meant, I simply have no remaining urge to try to explain to a large number of folks who confuse pretty basic constitutional law concepts, but want to argue with each other, what those concepts are. Not because i find it beneath me, but because it becomes exhausting :) Things like the substantive due process clause, the equal protection clause, etc, have a lot of precedent on them, and are very well studied. I would strongly suggest you take a look.