I'll be primarily drawing upon Marco Polo's own record of his journey, so I apologize for the lack of research material (though, to a much lesser extent, The Discoverers also covers this material).

But, the first thing you need to realize about the world in Polo's day was that the "white" race did not exist. In fact, race is an incredibly recent concept so far as it goes as a biological concept, and even up through the 1800s and early 1900s it was common to see people use the word and concept in the same sense that Polo would.

Polo would not have seen himself as white, which didn't quite exist at the time, but as a citizen of Venice and an Italian. He also wouldn't be nearly as prepared to see other "races" as lesser, because Europe was highly populated with thousands of different "races."

Now to answer your actual questions.

Polo saw all of the people he met as fully human, just like himself. They were different "races," certainly, but no more different from himself than Greeks or Germans or French. Their religions did not trouble him, though during his time as one of the Khan's favorites he made great strides in bringing Christianity to China (had there been a more efficient Catholic Church, the east-west divide may not exist as we know it). Polo wrote about them with delicacy and honor, and when writing about people and places he knew well, he wrote with affection.

European cultures were so wildly different, at that time, that Asian practices were no more alien than German practices. It was only another nation with their own customs.