Reason is very useful, as long as you reason using facts and sound premises. On the other hand, Fake news has demonstrated if you reason, using lies and false premises, you can lead people astray with what appears to be sound logic.
Remember the collusion delusion. If Trump had been working with the Russians, that would have been very serious for the country. This logic was sound, however, the premises and facts were false, so the logic did not add up to reality.
If I said the moon was made of cheese and if we colonized the moon and harvest the moon cheese we could feed the poor of the earth. This is logical, but it is type of logic that uses a single faulty cheese premise, to make the entire logic chain void. Logic is like a mathematical equation. If we input false data into the equation, it will still generate results. This is how the left wing base is fooled by its leaders with daily fake news.
Humans have been able to reason for centuries. What they lacked was not the ability to reason, but access to sound premises, due to not yet knowing all the facts of reality. If the earth was flat and finite it would have an edge. If you sailed to the edge you would fall off. This is sound logic but with faulty premises. Once we found out the earth was round, then the logic train changed, since the new premise led to different logical conclusions.