Your deflection about the media is entirely unrelated to AI, but it only backs up my argument. If giant media corporations are biased, why can't AI researchers be?
Every institution has biases, and blindly trusting a dataset from e.g. a police department is just as bad as blindly trusting data from CNN or Fox News. The collection, aggregation, and sharing of data is a biased operation. If a political or for-profit entity gives you data, it's going to be data that supports their agenda.
It takes active, conscious effort to combat that bias, in the same way that it takes active, conscious effort to not just get all your news from one source. The concern (which has been demonstrated) is that that isn't being done