For example, say there are 20 million on-line gamblers, and that 40% are not affiliated with either party. That computes to 8 million people. These 8 million understand it was a Republican senator that made this happen. Many of them will be less likely to vote for a Republican candidate now. That could make the difference in many tight races. Now do you understand?
I completely understand your numerical assessment. I just totally disagree that the reaction will be what you and he think it is going to be. First, I think most gamblers are likely to simply work around it or ignore it. After all, this stuff has to be enforced. I doubt banks will immediately do that, because they don't know which sites are 'illegal' without some tipoff. Second, I doubt it will be enforceable, either, as the gamblers will simply transfer funds to international banks that WILL transfer to the gambling sites. So I don't think players will care, because the sites will continue as usual.
But that said--I doubt a substantial percentage of players vote to begin with, and those that will vote won't do so primarily on the basis of this ban. Frist gambled that was the case, and I think it was a good bet (pun intended).