I don't necessarily disagree with you Twin, but there have been plenty of examples of steroid use within the UFC, when the baby face assassin (can't remember his real name) beat Randy Couture for the title, it was later uncovered that he had used steroids and tbh, looking at his eyes when he won it was quite apparent.
Yes, he was stripped of the title and Randy was offered it back, which he refused claiming a loss was a loss no matter the situation. But once old baby face was confirmed as clean he was allowed to compete again.
The same has been done for Chris Leben, who has, if I remember correctly been tested positive for steroids at one time and also for cocaine. He was also temporarily banned but allowed to compete again once proven his system was clean again. Another example is Chael Sonnen who tested positive for a form of performance enhancing drug when he almost beat Anderson Silva. Not only has he been back he has had another title shot since and is due for another one in April against Jon Jones.
So although there is part of me that agrees with the statement that they have cheated and should not be allowed to compete again, I do think you will see fighters like Cyborg back as the UFC has not yet permanently banned anyone for taken any form of drug, performance enhancing or not.