There's something worse than Roids and missing weight. And that's weight cutting.
Seeing a fighter that should clearly be fighting in a different weight class, starve himself and drain himself to death to make weight, only to show up in the fight looking like fucking hulk hogan should be downright criminal and it happens way more often than not.
The reason why it is worse is that people don't even see it as cheating and it can be more dangerous than having a fatass or a roided freak on the cage.
Now weight cutting can be a part of missing weight, if a guy missed weight because he cuts so much that he just couldn't make it then fuck him both for trying to cheat AND being a dumbass.