It is often held up as an ideal for free debate that all ideas should be brought out in the open.
Humanitarian, racist, xenophobic, liberal, conservative, communist, capitalist democratic, ecological, socialist, religious, and more: all these ideas and philosophies should contend in free competition, and the better will vanquish the lesser. Whether this debate threatens any political power structures in irrelevant as far as the validity of the ideas goes (although we all know that authoritarians often oppose ideas that would threaten their rule). Any ideas that require support by force are by definition inferior, because they cannot stand on their own.
It is assumed that in a fair debate, the winning ideas will be those of the more compassionate, such as tolerance and fair play. How true is this, really?
Are there really any truly dangerous ideas out there? Ideas that are logically unassailable, but would lock us into some mode that would make us less flexible and able to respond to the challenges of the world? Are there ideas that would crash our minds, that would threaten humanity as a whole or even all life? Or is it more a case of differing, incompatible axioms, so that debates never get started on the same playing field?