Islam incorporates the ultimate devaluation of non-Muslims in the most obvious way by teaching that while a Muslim may be punished with death for murdering a fellow Muslim (Bukhari), no Muslim can be put to death for killing a non-Muslim (Bukhari - Muhammad: "No Muslim can be killed for killing a kafir."). The Quran’s "Law of Equality," which assigns human value and rights based on gender, religion and status, is the polar opposite of equality in the sense intended by Western liberal tradition, which ideally respects no such distinction.
One can always find apologists willing to dismiss the harsh rhetoric of the Quran with creative interpretation, tortuous explanation or outright denial, but their words and deeds almost always belie a concern for Islam's image that does not extend to Islam's victims - at least not with the same sense of urgency - thus proving the point.
Of course, there are also exceptional Muslims who do not agree with Islamic supremacy and sincerely champion secularism and respect for all people. Some even find verses or fragments of such to support their independent beliefs. But, for these people, the Quran as a whole will always be a constant challenge, since it explicitly teaches the distinct and inferior status of non-Muslims.