Despite the best efforts of journalists to be objective, it is inevitable that their own biases will enter their reporting, even if inadvertently.
Conclusion (therefore)
It's imperative that trained editors look over journalists' work with an eye towards finding and removing biases, to make reporting as objective as possible.
Evidence
It's inevitable that bias will enter journalists' reporting, even if inadvertently.
Evaluate
Given that ... bias will inevitably creep its way into journalists' work,
How could we argue that ... it's not imperative that a trained editor look the work over to find and remove bias, in order to make reporting as objective as possible?
We might feel this argument as a Plan / Goal, or a Problem / Solution type conversation. The problem is bias. The goal is to remove bias. The plan/solution is to have trained editors scan for bias and remove it.
When we see an author say, , there are two different types of assumptions:
the author is assuming that her recommendation, Y, actually helps to address problem X
the author is assuming that there aren't other ways to address problem X
Goal
So the author needs to assume that trained editors will be able to detect bias, they'll be motivated/willing to comply with removing that bias once detected, and this won't backfire in some way (the editor's omissions won't actually inject the editor's bias into the final reporting).
And the author also needs to assume that there's some other way to address bias that would be at least as effective as trained editors (even if that comparable level of effectiveness is "has no meaningful effect").