Onan the barbarian?

One more reason to read the TLS, says Robert Fulford:

Spare a tender thought for Onan: Has anyone in the Bible or anywhere else ever endured such slander? Imagine having a sin named after you when there's no evidence you ever committed it. For three centuries or more, "the sin of Onan" has meant auto-eroticism. Even the dictionaries libel him. Look up "onanism" in Oxford and the first word you see is "masturbation."...In truth, Onan was not (how shall I put this delicately?) a wanker. Check it out in Genesis 38. It says he practiced coitus interruptus, nothing else. The man was a pioneer of birth control.... The TLS, circulation 35,204, founded in 1902, may be the only paper that can be counted on for a forthright discussion of Onan.