It's their way of implying they're unbiased, but 50/50 comaints doesn't mean unbiased. In fact it probably means there's a bias, if it's about a specific subject only. The facts only is unbiased, but for many people on many subjects, the facts are upsetting.

For example, climate change is real and has been known about for over a century. Reporting on that would be unbiased, but you'd get a lot more complaints from a certain segment of society than another. Managing to get 50/50 means you biased your report to be in the middle. The middle doesn't mean unbiased.