So, in one sense, those (mostly right-wing) critics of those who broke the stories are right: No one should be judged for the behavior of his teen years. I'll admit that I am speaking out of self-interest: I did a bit of bullying myself. However, I was also bullied and although I don't think I want to see my old tormentors again (for reasons other than the bullying), I expect, or at least hope, that they have grown out of such behavior and the attitudes behind them.
However, it seems that Romney hasn't progressed much, in his attitudes or actions, since his teen years. If anything, he's worse now because he has a greater platform and more resources to perpetuate his repressive and predatory actions. For starters, he looks like a champion of gay rights only in comparison to Newt Gingrich, Rick Santorum and others who ran against him for the Republican Party's nomination to the Presidency. It's one thing to oppose gay marriage. (I favor legalizing it only because it's the best we can do in the current legal system; I actually believe the government should play no role at all--save, perhaps, to set a minimum age--in determining who should be allowed to be married.) He also opposes civil unions. Still, that's not the worst of his positions: He supported, until its repeal, Bill Clinton's "Don't Ask, Don't Tell" policy. Worse still, in 2006 he rescinded the support he gave to the Employment Non-Discrimination Act twelve years earlier, saying that it would "unfairly penalize employers at the hands of activist judges."
But Romney's grown-up bullying doesn't end with his blatantly homo- and trans-phobic policies. He also will throw workers and even managers under the bus. Bain Capital, which he headed, was known for buying companies and running them into the ground to make money. Along the way, they'd fire workers, including managers, and install their own managers, most of whom knew nothing about the industries or products of the companies they were running. And Bain would charge exorbitant management fees. Really, what they did was the corporate equivalent of a home invasion.
So, in a way, he hasn't changed since he was a teenager: He is perfectly willing to exert force on people less able to defend themselves than he or his cohorts are. The only difference is that now he doesn't use physical force.
If you want to read about more examples of what I've just described, look here, here, here and here.