Sometimes - as in Julian's appalling treatment of the lower orders in the Famous Five books - these archaic attitudes are now very funny. Most of the time it's just eye-roll-inducing - the sort of thing you have to put up with if you want to read almost anything pre-1970. But in some cases the bigotry is so extreme and gratutious that it actually prevents me from reading on.
For example. References to gay and lesbian characters in older books can often be casually derogatory, but in many cases references to "pansies" don't seem to contain anything more than ignorance. Unfortunate and unpleasant, but not intentionally cruel or nasty. In other cases, however....well, a few years ago I read my first Ngaio Marsh novel. It was pretty good, and soon afterwards I picked up a batch of her books. However, the next one I read - Death in Ecstasy turned me off her books forever. The depiction of the gay characters was so deeply, deeply unpleasant - not only were they pathetic, whining grotesques, but entire paragraphs are devoted to other characters saying what "beastly, disgusting things" they are - that it went far beyond the casual prejudices of the time. It was horrible, and I never want to read another of her books again.
When I was a kid, I loved Enid Blyton's Adventure books (The River of..., Circus of..., Island of... et al). I was well aware of Blyton's snobbish, sexist and racist attitudes when I was small, but while I reacted to some of her statements with outrage (encouraged by my parents), I could still read and enjoy them, accepting her attitudes as being of their time. Recently, however, I had the urge to read one of the Adventure books again, and picked up the River, in which the children travel by boat down an African river. However, I had forgotten that this is the book in which Philip, the child whom all animals love, becomes the idol of a young native boy with "wild rolling eyes" who calls Philip "Massa" and who insists on sleeping on the floor at his feet. It was just too disgusting to ignore, and I couldn't finish the book.
So where do you draw the line when it comes to older fiction? When does casual archaic bigotry become gratuitous bigotry? And what books can you just not read because of that?