Argus, you keep referring to elites. But I think that the existence of a neoprogressive media bias doesn't require elites at all, and perhaps a better explanation doesn't involve them.
I think the reason you see such bias is due to a combination of noble cause corruption and cronyism. Maybe call it noble cause cronyism?
Neoprogressives will often view those who are not neoprogressive as evil. Where as non-neoprogressives often view neoprogressives as simply stupid. As a result of this, when it comes to hiring decisions, if a neoprogressive is making the hiring decisions they are likely to favour other neoprogressives 'for the greater good'. Where as non-neoprogressives would generally be more fair in hiring decisions and care more about merit. As a result of this, even if the people making the hiring decisions are a mix of neoprogressives and non-neoprogressives, the net result is a favouring of neoprogressives when it comes to hiring. And as neoprogressives are more likely to get hired, promoted, etc. they become more likely to get in positions where they make hiring/promoting decisions. And as the concentration of neoprogressives gets higher, the neoprogressive hiring preference increases. Which means that as one moves up in the hierarchy of certain organizations such as the media, the concentration of neoprogressives increases. In effect, the neoprogressive in-group preference that is due to noble cause croynism causes excessive concentrations of neoprogressives in positions of power.
This is why we see strong concentrations of neoprogressives in the media (especially cbc as it is government owned), academia/universities and the public service (these areas don't have to worry about profit maximizing / meeting the bottom line and are more attractive to neoprogressives as they allow the neoprogressives to change the direction of society 'for the greater good'). Want to have your paper published? Well if it has a neoprogressive slant then it is more likely to get published. Are a journalist and want to move up in the organization? Well if you run some stories that support various neoprogressive narratives then your neoprogressive bosses might be impressed and will be more likely to hire you. Etc.