Since the beginning of the current wave of Palestinian violence, in September 2000, Hamas has perpetrated 52 suicide attacks, in which 288 Israelis were murdered and 1,646 were wounded. THERE IS YOUR ANSWER. The US is fighting a war against radical Islamic terrorists. How could they possibly recognize Hamas as anything other than what it is.
Roadside bomb kills five border officers in western Iraq (AP)
from the article: U.S. tells Israel it will shun PA gov't that includes Hamas