You can now opt out of offensive quotes by setting your preference on your profile page at:
(near the bottom of the page)
Note that by opting out of possibly offensive quotes you are removing nearly 1,000 quotes from the library. Different people find different quotes offensive for different reasons, and to be frank, the majority of what has been flagged as offensive seems fairly tame to me. But nevertheless, if you'd like to opt out of viewing any potentially offensive material, the option is now there.