If Allah commands, "kill the pagans wherever you find them" (Qur'an 9:5), then what, exactly, is the difference between a "moderate" and an "extremist"?

"the Messenger of Allah . . . would say: 'Fight in the name of Allah and in the way of Allah. Fight against those who disbelieve in Allah. Make a holy war. . . . When you meet your enemies who are polytheists, invite them to three courses of action. . . . Invite them to (accept) Islam; if they respond to you, accept it from them and desist from fighting against them. . . . If they refuse to accept Islam, demand from them the Jizya. If they agree to pay, accept it from them and hold off your hands. If they refuse to pay the tax, seek Allah's help and fight them . . .'" (Muslim Book 19, Number 4294).
"fight and slay the Pagans wherever ye find them, and seize them, beleaguer them, and lie in wait for them in every stratagem (of war) . . . " (Qur’an 9:5).

"Fight those who believe not in Allah nor the Last Day, nor hold that forbidden which hath been forbidden by Allah and His Messenger, nor acknowledge the religion of Truth, (even if they are) of the People of the Book, until they pay the Jizya with willing submission, and feel themselves subdued" (Qur'an 9:29).

"The punishment of those who wage war against Allah and His Messenger, and strive with might and main for mischief through the land is: execution, or crucifixion, or the cutting off of hands and feet from opposite sides, or exile from the land: that is their disgrace in this world, and a heavy punishment is theirs in the Hereafter . . . " (Qur'an 5:33).
[Ibn Kathir says of this verse: "'Wage war' mentioned here means, oppose and contradict, and it includes disbelief, blocking roads and spreading fear in the fairways. Mischief in the land refers to various types of evil." So, Muhammad requires execution, crucifixion, or cutting off hands and feet from opposite sides for "disbelief."]
"Allah's Apostle said: 'I have been ordered (by Allah) to fight against the people until they testify that none has the right to be worshipped but Allah and that Muhammad is Allah's Apostle . . . '" (Bukhari Volume 1, Book 2, Number 24).

"It is not for any prophet to have captives until he hath made slaughter in the land. Ye desire the lure of this world and Allah desireth (for you) the Hereafter, and Allah is Mighty, Wise" (Qur'an 8:67).

"Allah’s Apostle said, 'I have been made victorious with terror'" (Bukhari Volume 4, Book 52, Number 220).