Some critics gripe that going after Mr Assange for hacking is like going after Al Capone for tax evasion—that it was the only charge prosecutors think they can make stick.

that引导原因状语从句，that可以改为because

译文：一些评论家抱怨说，追究阿桑奇的黑客行为就像追究阿尔·卡彭的逃税行为一样，因为这是检方认为他们唯一能站住脚的指控。