You're kinda right. Katherine is the one that compelled Stefan to drink her blood. But if you look at it from Damon's prospective, he loved (and kinda still) Katherine, and Stefan was his rival. Damon thinks that if Stefan has just got out of their way, he and Katherine could have been together for ever.

ya it wasnt stephans fault that katherine wanted him and damon to be vampires stephan didnt have a say if katherine turned him cause she compeled him but damon on the other hand wanted it

Agree...He should be mad at Katherine,not Stefan.But I guess love makes you blind...=)

yeah i definately agree :)

well i dont think that he does hate him that much i think he loves Stefan really

not true, stefan saved him.