Perhaps I'm missing something but I don't see the two forms of extremism in the same light at all.

Muslims in the Middle East aren't sending their military forces to invade the West. Nor are Muslims propping up brutal dictatorships that oppress western peoples. Nor are Muslim nations bombing western nations to bring about a change of government. Nor are Muslim companies exploiting Westerners and their lands. All of those things, and more, are being perpetrated by western countries against Muslims in the Middle East. That's the reality.

The politics underlying western right-wing extremists and Muslim extremists are not the same. The tactics and rhetoric may seem similar, but the two positions aren't born of the same injustice. Muslim extremists are retaliating against grand-scale systemic western oppression of their people. Western right-wing extremists don't have that justification.