I found this passage to be particularly difficult

You're absolutely right that this is a very nuanced passage. The first passage expresses a critique of a view in no uncertain terms, and the second passage is a critique of the first passage, agreeing in part and disagreeing in part. I think there are a few ways we can approach this. First, I would highly recommend taking your time reading. It's going to be nearly impossible to fully understand this passage if you're rushing and only skimming. I would recommend not moving on to the next set since until you feel like you've really understood the sentence you're reading. I also like noting down authors views in my own words. For example, I would try to express the first passage's view in one sentence if possible, and then use that understanding as I navigate the second passage. Finally, I find that taking a position can be quite helpful. Do you think that plagiarism is an appropriate or useful lense through which to view historical works? I think that taking a side can help you to not only see arguments clearer, but to think of an even anticipate where the authors are going.