Wrong. You don't have to be a birther to oppose Obama. In fact, you're likely to be more effective if you aren't a birther.
9/11 Truthers who post here would likely say the same stuff about "disrupting" their threads, by contradicting their theories. Too damn bad. They post false arguments, they get people telling them so. Birthers are no different. That's not "disrupting" the thread unless one thinks the thread should only be pro-birther. Well there's absolutely no reason to have such an expectation.
Comparing birthers to truthers is like comparing Paul Revere to Benedict Arnold