Tax benefits, hospital visitation, inheritance issues, insurance costs...and on, and on, and on.
Things that heterosexual couples take for granted that gay couples could not prior the the legalization of marriage equality nationwide. Do this: Be in a heterosexual marriage for 15 years, and follow your spouse's ambulance to the hospital. Then have a nurse deny you access to their bedside because your "marriage" offends her sensibilities. This same shit had to be fought over interracial marriage as well.
Perhaps your spouse dies in that hospital. Now have their family swoop in and take away your home, along all the money from your spouse's bank accounts. Sure, they could set up trusts and contracts and PoA's, but the point is, I'm married, and if I die, my wife by default is my next of kin. I don't have to do any of that noise, and neither should someone else just because they're gay. Inheritance and capital gains were an even worse issue.
Try having a shred of empathy for people whose circumstances are different from yours, how does that sound? Gay people don't necessarily care if people "like" their marriage, but they should be equal under the law. Statements like yours sound like they're straight out of 1963 and just repurposed from "Coloreds" to "Homos".