Since when is CNN left?
Since forever. It might not be as far left as MSNBC, but it is left just like ABC, NBC, and CBS. Attracting money by mimicking FOX News might be a temptation, but it goes against the DNA of the writers, editors, and anchors. It's like Hollywood where all the biggest blockbuster films are PG and PG-13 rated and cater to family audiences; yet all the producers keep spitting out films that have very restrictive ratings (R, NC-17, etc.) because that's the kind of films they like and somehow wish that everybody else did.
"Tell the truth and run." -- Yugoslav proverb