It is true that he did indeed headbutt, but it wasn't as if Katsidis was fighting like a girl scout either. I thought Katsidis handled Casamayor's dirty(er?) tactics quite well and wasn't afraid to respond in kind. Nor did it really seem to get in Katsidis' head either. Most importantly it had very little to do with the eventual end of the fight as that was more a result of Katsidis' getting too eager and getting tagged by a sweet counter.
Actually I believe katsidis was mad at his dirty tactics...he even took casa and threw him to the floor
Casa is a damn dirty fighter. Headbutts, low blows, holding, wrestling and grabbing is what everybody expect from him.
After the point was deducted for low blow I said to my brother 'it only takes not gonna be knocked out from katsidis to win this fight'... and 2 minutes later - booom. How one judge could have Casa ahead. They were even on points deducted and Katsidis won almost every round.