Just excuse him while he's stunned silent by the spite and total bullshit behind that statement. He's surprised that it actually hurts to hear. Since when did he get fond of this asshole?

"Right. Good luck on getting a life, asshole." And what more is there to say? He almost feels like lashing out at Peter, but that'd only give him more fuel for his arguments. Instead, he pushes past Peter and out into the crowd of people, slipping his mask back on as he goes.