The BBC suffers from embedded organisational bias. Over time an organisation acquires an ethos and then hires only people who share the same ethos. As everyone in the organisation thinks the same way, they view anyone who thinks differently as being wrong and that they are guardians of the standard, Politically they're biased to the left, favour "diversity" and hire accordingly.
As another example, the armed forces have their own ethos, especially within the officer corps, and retain many quaint Georgian traditions of behaviour that are no longer shared by the population at large.