Yeah, many Spaniards converted to Islam. True. That is true about the Amerindians in Mexico and all the mestizos produced too. Eh... Jesse Jackson and Al Sharpton like many black Democratic leaders are bible preaching Protestants and not priests of Voodoo.
I don't think it should be a surprise that Spaniards would convert to the leading and wealthiest power group. Pretty typical human trait.
Islam offered some benefits in other ways as well. Islam brought a solution to the violence and social problems throughout the Iberian region of that time. That Catholicism was inadequate to handle or address. Kind of like the Nation of Islam today offers a solution to the violence and social pathologies within Black-America in a time in which the Black Church (Protestant) has been incompetent and incapable of adequately addressing and solving.
Islam will offer solutions to America's and Europe's problems as whole as secular people provide utterly incompetent leadership, social pathologies explode, and secular leadership is up for the highest bidder with the best story to tell the masses.
It's presumptuous to dismiss conversions as something done only for materialistic gains and not because they saw Islaam as the truth. This argument of conversion purely for worldly pursuits falls short when we observe that a large number of Muslims stayed true to their faiths even when facing death or expulsion. Many "left" Islaam publicly but were still practicing secretly.
I mentioned conversions in the first place because you brought up how Spaniards didn't support Muslim rule. Clearly many of them did if they converted to the religion. Perhaps Christian kingdoms didn't support Muslim rule, but that's different from saying 'white Spaniards'.
I do agree with Islaam being the cure to societal ills and the concept of justice probably attracted many to the religion in the first place.
But in terms of the "Dark Ages," for one, Western Europe in no way constituted most of planet earth. Secondly, the term itself is propaganda.
Be that as it may, the Muslims were far more sophisticated than much of Europe, despite being the new kids on the block.
The Muslims acquired a lot of their "knowledge" from the Eastern and Oriental Christians. Particularly the Oriental Christians. And a lot of their "knowledge" from the Hindu Indians. That learning they translated into Arabic and then brought to the Christian West.
This is some major downplaying of Muslim contribution to society but I guess it's to be expected. I remember back in high school, history classes would be very Eurocentric: European countries, European culture, and European achievements would get an entire week or more and the Islaamic period would get like...3 paragraphs (or maybe a few pages if they were feeling particularly generous). I only got to learn more about some parts of Islaamic civilization in the secular setting when I took a class dedicated to Middle Eastern history at my university. If this is how our education system treats that region, that culture, and that religion in that time period, it's not surprising to find people minimizing the Muslim contribution to many fields. I want to include a quote that's relevant to what you said, but I don't want to make my post too long. I'll provide it in the next one.
By the way... the "Golden Age" of the USA was arguably right after WWII during the 1950s to the late 1960s. Why would Black-Americans rebel during a "Golden Age" and one of material prosperity and scientific advancements that greatly surpassed the Golden Age of Moorish Spain?
I won't really get into/debate the "golden age" of the US surpassing the Golden Age of Spain.
The US wasn't very just towards blacks. Historically, Muslims treated their subjects much more justly than those who ruled the subjects before/after the Muslims (despite sometimes being massacred by people of the same religion as those subjects).