Obama is taking criticism because his reverend, Wright, said some comments about America being partly responsible for 9/11. "Chickens coming home to roost" and all of that. Here are some thoughts.
1. The idea of 'blowback' was presented in the 9/11 Commission Report and describes that actions may have unintended consequences. This isn't a new idea, and it isn't anti-American to suggest that blowback is real.
2. Reverends Falwell and Robertson blamed America for 9/11 as well. Video link is here. Although in their case, the culprit responsible for the terrorist attacks was not blowback, as Wright claimed. Rather, it was moral depravity.
So lets recap. It is anti-American to suggest that covert CIA operations in foreign countries can cause resentment in the local populace. However, it is perfectly reasonable, but not anti-American, to suggest that belief in evolution or partaking in gay sex causes terrorism.
For the record, and to my eternal dismay, John McCain long ago accepted the endorsement of Falwell and spoke at his "university". Anyone who would think less of Obama for his association with Wright should think still worse of McCain for his association with Falwell.
For the record, I could care less about either. It would be impossible for a person to become a contender for the presidency while never once associating with some mildly scrupulous characters. Relative to other politicians, both McCain and Obama are very clean.