A lot of people may not think being against casinos at the federal level really matters, including Representative Capuano, but I'd like to disagree. Here's two reasons why it matters:
1. The Supreme Court recently ruled against the ability of native tribes to have the wide latitude of opening casinos up, based off of having just one form of gambling in a state that are a part of broad, federal classes -- so if a state allowed poker, a tribe could create a casino with slots. However, it was one of those rare Supreme Court cases based on legislation, not Constitutional Law, and there have been efforts to reverse the Supreme Court's decision legislatively. Suddenly, a Senator's vote on the casino issue is actually quite important.
2. Internet Gambling is another a hotly contested issue on Capitol Hill -- and something potentially very dangerous, because suddenly everyone could gamble from their computer -- given that access and addiction are highly correlative, I'm sure many could see the potential danger there. If casinos and slot parlors offer negative overall economic growth in regions with their facilities and employees over the long run (and they do), imagine what kind of negative growth one would get with internet gambling -- with no jobs and no infrastructure.