Genre labels are a bit broad these days. I think a lot of classic fiction would be called Romance novels by today's standards. Are they? Is Thomas Hardy's Mayor of Casterbridge a romance novel? Is DH Lawrence's Women in Love?
In the days when they first published, their works... especially Lawrence's...were classified by some as pornography. Imagine that. The title "Lady Chatterly's Lover" still brings forth the image of being risque.
Times do change our perceptions, don't they?