What did Ponyboy mean when he said "Some of us never cry at all"?

In this quote, Ponyboy isn't talking about himself, he is referring to Dally, Two-Bit, and Tim Shepard..... and others like them. Ponyboy is referring to the people he knows who've become so distanced and detached that they are without emotion.... they're tough, independent, and they're hardened. The tough childhoods turned them into even tougher young adults.