Reason?

Excuse the subject matter but “Bestiality & me” makes a good point about the limits of reason.
If anything can be justified by reason, then either everything is permissible, which obviously is leading us already to a very dark place (don’t make me tap the sign), or reason is not always correct, in which case the last 250 years or so have been a catastrophically disastrous failed experiment in man’s hubris and arrogance.
I think this may have been pointed out to us a couple of thousand years ago, but we never listen.