When the public learned this week that notorious cult killer (and lifetime prison inmate) Charles Manson had acquired a marriage license and would soon wed his longtime confidant, marriage equality supporters reacted with outrage on social media.

“80yo Charles Manson will soon be getting married, but by all means don’t let gay couples destroy the sanctity of marriage!,” HRC president Chad Griffin remarked on Twitter. Author Christopher Rice added, “Charles Manson is getting married in prison, but by all means, Supreme Court, take your sweet time with my personhood!”

Indeed, the Manson marriage serves as a stark reminder of the egregious double standard that exists under the law for straight couples versus gay couples: while consenting heterosexual adults can get married in all 50 states and the District of Columbia, there are still 17 states where that very same freedom is denied to someone who wants to marry a same-sex spouse.

The silence of marriage equality opponents like Maggie Gallagher, Tony Perkins, and Brian Brown — who love to wrap their defense of marriage discrimination in lofty terms like the “sanctity of marriage” — exposes the sheer bankruptcy of that argument.

After all, as Michael Knaapen wrote on The Bilerico Project, if you’re cool with one of America’s most objectively horrible people getting married, what kind of mental gymnastics does a person have to go through to justify their opposition to legal recognition for the marriages of good, decent LGBT Americans?

Some people took things even further, though, claiming that Manson’s marriage somehow threatens or hurts the rights of same-sex couples; others even said they didn’t think he should be able to get married at all. But as satisfying as those arguments may seem, they actually betray the very ideals of marriage equality.

Don’t get me wrong, I am absolutely not defending Charles Manson -- the evil that lurks inside that man’s heart and the monstrosity of his crimes are beyond dispute. But they’re also beside the point, which is that everyone deserves the right to marry the person they love — even if they’re old, even if they’re in prison, and yes, even if they’re a convicted murderer. As a marriage equality advocate, I’ve spent years arguing that moral disapproval of another person’s relationship is insufficient grounds to deny them the freedom to marry. I’d be the worst kind of hypocrite if I turned around and applied to someone else the same unreasonable standard that my oppressors have applied to me.

As to the argument that Manson’s marriage threatens the marriages of same-sex couples, that’s so laughably absurd that I could scarcely believe people were seriously making it. (No, honestly, when I read their comments I thought they were joking.) Charles Manson’s soon-to-be-legal union no more threatens my marriage than my husband and I threaten Maggie Gallagher’s. The phrase I often say to opponents of equal marriage applies in this situation as well: if someone else’s union threatens your own, don’t worry about their marriage — see a therapist about yours instead.

Marriage equality has moved so far in such a short time because we’ve successfully made the case that not just some, but all loving, consensual, committed adult couples should be protected equally under the law. Saying that Charles Manson — as odious a human being as he is — deserves anything less than we do is a violation of that fundamental principle. When it comes to the marriage, we would do well to remember the words of Abraham Lincoln: “Those who deny freedom to others deserve it not for themselves.”