Best religion for progress of humanity is the one that embraces work, tells people to treat each other fairly, and otherwise keeps its hands off from irrelevant details of people's lives - things like what consenting adults do in bed, what they eat or drink, what they can or can't say.
Unfortunately Christians have been historically way too focused on the bad parts while ignoring the good parts, leading to madness like wars between Catholics and Protestants and discrimination of minorities. Think of the current conservative elite in America for example - it's hard to find people who are further away from teachings of Jesus Christ than those greedy, hateful idiots.
This is hilariously untrue, if one is talking about the Western Roman empire. An islamic state did conquer Constantinople, which I presume is what you mean.
The Roman empire (western) basically fell apart due to infighting more than anything else.
eg: https://www.theguardian.com/world/ng-interactive/2021/sep/06...
There's a long list of questionable behaviour, eg. enslavement for Jesus: https://en.wikipedia.org/wiki/1838_Jesuit_slave_sale
Meanwhile, in history, religions enslaved people.
Returning to the point you keep dodging, that includes Christians.
I have no idea what that sentence is specifically meant to mean, that aside, western countries have had actual slavery and effective slavery both in the past and the present.
eg: Past & actual: https://en.wikipedia.org/wiki/1838_Jesuit_slave_sale
'Present' (Post WWII) & effective: https://www.abc.net.au/news/2014-04-27/child-abuse-royal-com...
I don't mean to exclusively beat on Christians or just Catholics here; but I do intend to counter your apparent narrative of good Christians and evil Muslims.
Christians certainly diminished a lot of cultures, just as other religions also did - the initial point that started this above.
There has never been as many slaves in humanity as there are in the US' prisons.
What's that? Oh, they don't count because they're criminals?