"Think for yourself" is humanity's adaptation of forager ants[0]. Sure, many will be lost, but we need those people that hunt for novelty because it eventually benefits everyone else. You could even think of historical figures that advanced society as the forager ants of our culture. I'm not sure what the benefit would be if everyone chose to be one, though.
The hive mind is an interesting phenomenon, it seems that there isn't a right or wrong way to do things. Anything we do is a behavior which ripples its effects way beyond our understanding. One thing seems certain though; if a behavior is there, it's been selected by evolution. So, there has to have some advantage at some level even if it isn't obvious at all.
Regarding Chesterton's Fence, it's something I've been noticing myself as my understanding grows. Though I didn't know the term, I do see it more and more around me. I have the feeling that one example of this behavior can be spotted in today's strict Muslim society, where women are covered head to toe. As westerners, we see it as a very absurd thing to do for the sake of a religion. But do we really understand the whole story? Seeing how we ourselves quickly rushed to cover our faces to avoid catching a contagious disease, I'm speculating that something similar might have been the initiative for such a cultural artifact. Which are the most vulnerable and most valuable people in a society? Women, obviously, we have to protect them. Perhaps in similar disease outbreaks in the Middle East, people figured out that by reducing contact with your environment actually reduces the possibility for illness and death.
It perhaps then, eventually creeped its way into religion, because you had to make sure people would follow the advice even if they didn't understand it, and that was the institution people listened to at those times and was more likely to be passed on to next generations. Survival supersedes freedom, so, there you have it.
[0]: https://engineering.stanford.edu/magazine/article/stanford-b...