Maybe steroids are like some recreational drugs or booze and it just magnifies your personality. So a hot headed douche is just more hot headed on roids. As George Carlin said "sure, it magnifies your personality, but what if your an a**hole?".
There are many different drugs and some likely have different effects on the system so maybe you can't lump them all into a bucket that says "they cause rage" or whatever. Drug A may increase rage where drug B does not. So I think it might be fair to say the results from one or a few person niether proves nor disproves harmful effects.