This happened to me and is a perfect example on why you need to know about the bad sites.
There was a person on an internet forum that was spewing a ton of untrue things that he said the Catholic faith was teaching. I kept telling him that what he was saying was not what the church taught. He finally told me the source he was using and it was a so called Catholic site, but one that seemed to make things up.
I don’t know what you mean about it not being in the set of things you are looking for, but if you don’t know where others are coming from cannot correct many wrongs.
What you are saying is true in a perfect world, but one that does not exist.