In response to other people's outrage at the cultural supremacy stuff. I think it's totally valid and good for us to tear something to shreds on the standards of our own time rather than excuse it for being "typical of the time period". It reminds me of the tortured logic I read in college trying to weasel Shakespeare out of being anti-Semitic. But in the interest of enjoying a story, it's often helpful to put the generation-gap blinders on at least until the story is over.
I'm not sure exactly what you mean by saying "tear something to shreds." It's inherently unreasonable to expect all authors at all times to share the values of early 21st-century Westerners -- attitudes change, even over a period of 30-35 years. The question is, how do you respond to those that don't?
If by "tear something to shreds" you mean simply, "note that the attitudes we now fund repugnant are there, maybe note why people at that time might have thought that way" then I think it's a perfectly valid approach. If you mean, "obsess over the objectionable elements to the exclusion of all else," that seems ridiculous.
I think the attempts you describe to "deliver" Shakespeare from being anti-Semitic represent the worst approach -- trying to insist that somehow, no, really, this author we enjoyed is
just like us even in the face of evidence to the contrary. OK, Shakespeare was an anti-Semite. Along with virtually the entire Christian population of Europe at that time. No, I'm not proud of that, but I'm not giving up
Henry V because of it, either. (Admittedly,
The Merchant of Venice is a tougher case -- story's not as good and the anti-Semitism is overt -- but I'll probably just hang a disclaimer on it and keep moving...)