As Aristotle apparently said "It is the mark of an educated mind to be able to entertain a thought without accepting it."
If we can't even discuss certain topics, if we can't even think things through, then we've entered the realm of thought police.
I ask this in a bit more depth here: https://news.ycombinator.com/item?id=14967029
I think the idea that we should suppress mere discussion of certain topics is very dangerous, and could lead society down a very dark path.
Let's not forget that things like interracial marriage, gay marriage and equality for women were once widely considered "abhorrent ideas".
As Aristotle apparently said "It is the mark of an educated mind to be able to entertain a thought without accepting it."
If we can't even discuss certain topics, if we can't even think things through, then we've entered the realm of thought police.