In societies that still don’t recognize same-sex marriage, there is a universal assumption, and intense social pressure, for heterosexual couples to have children. That is seen as the purpose of marriage, and life more broadly. And while the conceptualization of marriage has shifted away from that in the developed world, that is itself a contentious trend.
In the context of the US, your arguments are compelling, but they show exactly why the issue isn’t “morally indisputable.” It’s worth reading carefully through Obergefell. It spends a great deal of time establishing several things. First, that sexual orientation is innate and immutable: “Only in more recent years have psychiatrists and others recognized that sexual orientation is both a normal expression of human sexuality and immutable. See Brief for American Psychological Association et al. as Amici Curiae 7–17.” Second, that the understand of marriage had in fact changed to deemphasize children. Third, that new studies had shown that large numbers of same-sex couples were in fact raising children together. All of these established why same-sex unions should be protected as part of the fundamental constitutional right to marriage. Other approaches were possible and had been advanced. Some on the left wanted a broader rethinking of traditional marriage as a social institution. Obergefell could have treated marriage as just some government tax benefit, which was the libertarian view. Instead, it doubled down on the fundamental importance of traditional marriage, and the government’s legitimate interest in recognizing and promoting that institution, while expanding it to same-sex couples. It was very much the product of political debate and compromise amongst a variety of positions.
And in the end, this debate was ultimately a good thing because the political process fostered understanding and consensus. Same-sex marriage has become accepted quite rapidly. (Abortion rights, by contrast, remain highly contentious and no consensus has ever developed.)
In the context of the US, your arguments are compelling, but they show exactly why the issue isn’t “morally indisputable.” It’s worth reading carefully through Obergefell. It spends a great deal of time establishing several things. First, that sexual orientation is innate and immutable: “Only in more recent years have psychiatrists and others recognized that sexual orientation is both a normal expression of human sexuality and immutable. See Brief for American Psychological Association et al. as Amici Curiae 7–17.” Second, that the understand of marriage had in fact changed to deemphasize children. Third, that new studies had shown that large numbers of same-sex couples were in fact raising children together. All of these established why same-sex unions should be protected as part of the fundamental constitutional right to marriage. Other approaches were possible and had been advanced. Some on the left wanted a broader rethinking of traditional marriage as a social institution. Obergefell could have treated marriage as just some government tax benefit, which was the libertarian view. Instead, it doubled down on the fundamental importance of traditional marriage, and the government’s legitimate interest in recognizing and promoting that institution, while expanding it to same-sex couples. It was very much the product of political debate and compromise amongst a variety of positions.
And in the end, this debate was ultimately a good thing because the political process fostered understanding and consensus. Same-sex marriage has become accepted quite rapidly. (Abortion rights, by contrast, remain highly contentious and no consensus has ever developed.)