Instead of being told what to think of the USSC decision which legalized same-sex marriage nationally, you can read the decision right here.
With the dissents it is a fairly lengthy read.
This decision isn't going to change things too much except to make divorce lawyers more rich. There simply aren't that many gays and lesbians in the United States that it is going to have much of an impact on the vast majority of people. And yes, it does definitely redefine the purpose of marriage because it is saying that other purposes besides the raising of children and the perpetuation of a society exist. "Love" and "commitment" are actually pretty flimsy reasons to get married, but by far those are the reasons people get married. No wonder so many people get divorced since people are fickle. However, this really wasn't the aim of the LGBs; they wanted those legal benefits afforded to heterosexual married couples and not go the piecemeal route of civil unions. This was easier for them. Of course, many people aren't happy about this decision, but there isn't a hell of a lot that can be done about it. It's like Roe v. Wade. Granted, there has been some chipping away by the high court on that decision, but legal abortion nationwide is still the law of the land 42 years later. The anti-abortion crowd will never make it illegal again; all it can do be is be pains in the ass in terms of women's access to it.
Anti-same-sex marriage will merely be useful for the right to galvanize the supporters come election time, but not a damned thing is ever going to happen here.
Besides, our politicians are too busy trying to screw us over with ruinous trade agreements and other handouts to big biz, Wall Street, and the billionaires to give a shit about anything else.