Jon Jones can deny it all he wants ... but he cheated before BOTH his fights with Daniel Cormier, which makes DC the true champ -- so says UFC superstar Luke Rockhold.
The "B" sample for Jones' failed drug test came out on Tuesday ... which revealed a positive test for the same banned steroid he got popped for last month. Now, Luke says it's time we all faced the truth.
People - Jon - Things
"People can be in denial about Jon ... but he's taken things all along...