I read the article earlier today and I'm familiar with his line of thinking and work. Essentially, he's not a Christian because the "miracles" he speaks of are nothing more than things we can do sans supernatural help. Jesus, to Crossan, is more of a neo-Marxist than anything else. Crossan supports a more modernistic approach to Jesus, but it's really along the lines of Slavoj Ẑiẑek and his attempt to co-op Christianity into Marxism rather than pitting the two against each other.
Essentially, it's a materialistic view of Christianity, which is tragic and leaves us without hope.