Earlier quoted context omitted.
Because who is saying something colors the merit it brings. And as a healthy skeptic, knowing the direction to look for potential bias _does_ help orient my skepticism and find potential ulterior motives within the infinite space of "all ulterior motives". I certainly was asking myself "I wonder who was backing this" while reading it. (Don't take me the wrong way, I absolutely agree with you with respect to not filte…
> Because who is saying something colors the merit it brings Not at all; this is the "ad hominem" logical fallacy. ( https://en.wikipedia.org/wiki/Ad_hominem ) The claims being made are objectively true or false entirely independently of any personal attributes of the person making them. In other words, who is saying something is entirely irrelevant to the merit of what they are saying.
To bring this very hand wavy generalization back to the topic, look at many arguments posed in the anti-marijuana camp (as discussed in this very writeup) being based on extremely pessimistic to the point of unrealistic assumptions in order to derive the conclusions they prescribed; conclusions in isolation that could be seen as terrifying but if you consider author bias can be accounted for more reasonably.