The Muslim extremists didn't need to wait until Clinton and Obama went on Pakistani TV.
Nor are Clinton and Obama the only US presidents that have spoken publically about the US's religious tolerance.
More importantly, the current crop of Muslim extremists have had 50+ years of exposure to all forms of Western culture with which to inflame their followers.
The foaming-at-the-mouth reactions to the "infidel" is not limited to one or two aspects of Western culture, but to ALL forms of Western culture.
This attitude has been an intrinsic part of the Islamic worldview since the days of Mohammed.
Read up on your history of the Crusades or the Ottoman empire.