Expressing a moral disapproval of homosexual sodomy isn't a legitimate state interest.The State can undermine virtually any constitutional right it wants to so long as it can demonstrate a compelling State interest AND applies such a limitation equally.
Demonstrating a compelling interest is the language of strict scrutiny. In due process and equal protection challenges, that level of scrutiny applies only to laws that involve a fundamental right or create a suspect classification. Contrary to what you're claiming, it is very hard for a state to show that a challenged law is necessary to achieve a compelling government interest, as it has to do for the law to survive strict scrutiny.
I don't read Lawrence that way. What it turned on was the majority's decree that promoting the views of the majority on sexual morality is no longer even a legitimate interest of a state government. Evidently the fact the Supreme Court had never even hinted at such a thing, and the fact every state in the country had from the beginning taken for granted that regulating sexual morals was a legitimate government interest meant little or nothing to Justice Kennedy et al.
What Kennedy was picking up on was an idea expressed by Justice Stevens in his dissenting opinion seventeen years earlier in Bowers v. Hardwick, a decision that upheld a Georgia sodomy law and that the Lawrence majority claimed to be overruling. I say "claimed" because the opinion is very careful to leave in place the central holding of Bowers: that there is no constitutional right to engage in homosexual sodomy. The majority's reasoning in Lawrence was that the Texas sodomy law was unconstitutional not because it infringed some protected constitutional right, but because advancing the majority of Texans' moral disapproval of homosexual sodomy was not a legitimate governmet in
I don't know what you are trying to say. No state marriage law treats all would-be marriage partners equally, or ever has. They all discriminate against prospective partners when one or both is younger than a certain age. They all discriminate against prospective partners when one or both is already married. They all discriminate against partners who are more closely related by blood than some specified degree. They all discriminate against plural partners. Where is the equal protection of the laws, that all this flagrant discrimination is tolerated?