In response, proponents of marriage equality argue that opponents must have no serious arguments if they are reduced to "concern trolling."
Here's the thing. The concern trolls are right -- at least insofar as they predict a backlash. Opponents of gay marriage will no doubt get frustrated if they are ruled against, in the same way that abortion opponents were angered by Roe v. Wade. (But Roe was surely more of a shock to opponents than a gay marriage decision would be.) So, sure, there will be a backlash. Gay rights and abortion are very different issues, with different patterns in public opinion, but at least this much of the comparison is apt. People on the losing side of political conflict tend to mobilize.
A Court ruling in favor of marriage equality will not resolve all conflict over gay rights. There will still be bullying. There will still be hate crimes. Ask any African American if they think their struggle for equality ended after Loving v. Virginia in 1967.
Marriage proponents have noted the number of moderate Democrats and Republicans now supporting gay marriage rights. What was once an issue on which only social liberals differed from the rest of the country may soon become an issue on which only social conservatives differ. But they will continue to differ. And that means they will continue to pressure Republicans to be conservative. And some will be responsive.
But that's politics. You take your victories, and you keep struggling. It would be silly to not make progress because the other side will push back. If history judges marriage equality to be progress, it will never judge it to have happened "too quickly" or by the wrong means.