If you or I had to be balanced in something, then we would try our best. But its instinctive that we have preferences, bias and such, which will act out in the sub-conscious. If you hired a studio full of Igbos in Nigeria, they may say nice things about the Ogoni or northern tribes, but who amongst them can detect bias in the subtext and edit it to reflect real balance.The BBC still pretend to be impartial,at least Ch4 have the integrity to be honest about their bias.
People get annoyed at the BBC because it does not seem to have any real checks and balances. Particularly in its fictional output its all written by the same types of person and its current affairs is again through the lense of a narrowly minded group think.