The Los Angeles Clippers owner was fined $2.5 million and threatened with expulsion from the National Basketball Association after he was caught on tape making derogatory race comments.
Simmons, who is now a sports team co-owner with arena football's L.A. Kiss, calls Sterling and his remarks "heinous", but insists people should be able to say what they think in private.
He tells the Wall Street Journal, "I'm on Mel Gibson's side, Don Sterling's side and anybody who has a racist or an expletive rant privately. The difference between this guy and anybody else is that he was caught. He was ambushed. I think he should have done penance and paid a fine.
"If because you say an off-colour joke or make a racist rant privately that causes you to lose a job, nobody would have a job. Black people do it, Jews do it, Christians do it - everybody does it. I'm on the side of free speech in the privacy of your own home. Big brother has finally crawled in bed with us."
Following his race row earlier this year (14), NBA Commissioner Adam Silver told Sterling he would have to sell the Clippers. That is still ongoing.