Since NBC is owned by large corporations why does it have such a liberal bias?

All the evening cable shows on MSNBC have a definite liberal bias. Since NBC is owned by GE and Comcast, I would expect the shows to be much more conservative. Is it a money making issue because they know there is a large anti-fox audience?|||The demographics 18-49 years old who watch tv tend to be more liberal. They want their business.