I assume you are refering to Chapter Two of this great coming-of-age classic. This is of course when Two-Bit lectures Cherry and her friend on the differences between Socs and Greasers and the joy of fighting. Note what he says distinguishes the two groups:
Skin fighting isn't rough. It blows off steam better than anything. There's nothing wrong with throwing a few punches. Socs are rough. They gang up one on two, or they rumble each other with their social clubs. Us greasers usually stick together, but when we do fight among ourselves, it's a fair fight between two.
Therefore, in Two-Bit's opinion, the main difference between the Greasers and the Socs is that the Greasers are more honest and don't use unfair tactics to win their battles, such as ganging up on one person. Also, they are much "rougher" than the Greasers in the way that they fight, whereas the Greasers are fairer than the Socs. Both groups are of course violent and have fights, both between the groups and within them, but in Two-Bit's opinion it is the Socs who are the worst.