If you're referencing politicians I'm with you wholeheartedly; this piece is not about the government or politicians. Even when elected officials are well aware, as we have seen in the instances you reference and in the current crisis, they have behaved in ways that did not reflect the best evidence. Politicians have significantly more conflicting interests, and their continued practice requires that they appease voters.
That differs a great deal from the work of experts on an emerging crisis. I share in your dismay given that I know decision-makers had quality information, enough to act in a much more meaningful way, earlier.
Generally, scientists have been trustworthy. Researchers, especially in this crisis, have been trustworthy. Their entire field is essentially a search for and observing the truth. Rather than hearing critique from our opponents, we seek it from our peers and those most able to give it. Then, we don't disregard it.
We use it to make our work stronger. Specifically people in public health, so many of them could have gone to other fields and made significantly more money. Instead they stayed in a field that often goes unappreciated and they continue with or without public favor because it's not about being liked--it's about saving lives.
Are there exceptions? Of course. The length of these piece and style is not intended to cover the nuance that, rightly explored, would fill a book.