Question

在路上 原著里一句英文理解不来，向英语达人求解！

In the bar I told Dean, "Hell, man, I know very well you didn't come to me only to want to become a writer, and after all what do I really know about it except you've got to stick to it with the energy of a benny addict."

文中
after all what do I really know about it except you've got to stick to it with the energy of a benny addict." 理解不来

中文书中的翻译是：
我知道你来的真实原因，所以你不必把吸安非他明的劲都拿出来同我争论。

为什么会翻译成这样？请详细解释阐述一下，多谢了！
我觉得what do I really know about it不能翻译为我所知道的，因为我所知道应该是：what I really know about.

Answer 1

after all毕竟what do I really know about it 我知道你来的真实原因except除了you've got to stick to it with the energy of a benny addict把吸安非他明的劲都拿出来同我争论

Answer 2

after all what do I really know about it except you've got to stick to it with the energy of a benny addict 毕竟我所知道的，除了你已经把吸安非他明的劲都拿出来坚持要成为作家之外，别的我都不清楚。

Answer 3

用那种吸食benny（安非他命）的瘾君子所拥有的精神。或译为：就像吃安非他命的瘾君子那样痴迷