It's not extreme at all. I don't think that's the only thing a person should consider, but it has to be part of the picture. Secondary sources can have their ow

It's not extreme at all. I don't think that's the only thing a person should consider, but it has to be part of the picture. Secondary sources can have their own agenda. Also the simple fact that they have to choose what to include from the primary source means you don't get a complete picture. Even somewhat responsible scientific reporting falls into this trap: They may successfully report that something has a correlation, avoid implying a strong causal link, but then fall flat on their face by failing to realize that it was a low-powered study with very few participants. Tertiary sources are often reporting on secondary sources: The NYT reports on something that WaPo reports on. Any mistakes or biases present in the secondary source may be amplified & added to. I never read reporting about someone else's reporting without seeking out that first reports. At best, tertiary sources should be taken as commentary/opinion/interpretation. Non-primary sources are for when you want something explained to you in non-jargon terms or a TL;DR, or you want an expert's opinion on the primary sources etc. A medical study comes out about hear disease, and you want a cardiologist's assessment of the study. Even then, you need to understand who the cardiologist is. The average cardiologist may not be a great source: There are levels of expertise within any community, and I want someone who is at the top of the field. I don't want the average cardiologist's opinion. The problem is that no one has time to track down primary sources for everything they read/see/hear, or the level of knowledge to evaluate it. I'm fascinated by quantum computing, but I have no chance of understanding primary source research there. I have no choice but to rely on a secondary source or, if possible, the researchers themselves giving a higher level TL;DR. My rule of thumb is that, absent prior knowledge of bias/agenda/ill-intent, I skeptically take what people say at face value but don't accept it into my own views/opinions/etc unless I've done some digging of my own. If I'm not capable (e.g. quantum physics) of doing that, I simply try harder to get a variety of expert opinions, and avoid presenting anything I say/think as anything other than an outsider's imperfect understanding.