Even if it were all objective fact reporting, related facts can be left out that change the picture. Imagine someone reporting that some new supplement is correlated with a 500% increase in some specific deadly disease, and that whatever study that produced that number is bulletproof. Sounds risky! But the disease's base rate, not reported, is only 10^-6, so 500% over that really isn't that much.
Another fun one is if certain facts about overall dimensions of the data are reported but not about the individual dimensions themselves: https://en.wikipedia.org/wiki/Simpson%27s_paradox
Basically my point is even if we suppose these are objective facts, that's not enough to rule out bias determining which facts are used.