Because there are examples of the medical community getting it wrong (btw they did not get it wrong when it came to opiates - everyone knew opiates were addictive) doesn't mean they are always wrong.
Also there is no way for you to figure out who the quacks are (of course they exist, there are MDs suggesting insane things all the time) and who the correct but contrarians are.
So, by default you assume if the opinion is not mainstream it must have validity.
Now, I'm not saying the opposite is true. I'm saying it is just as bad (or maybe even worse statistically) to form an opinion because it isn't mainstream as it is to form an opinion just because it IS mainstream.
You're not a critical thinker because you dismiss the mainstream because it is mainstream. Just the opposite.