The word "educated" here may be joined with "matured". The reason youths who latch onto an ideology do so with such zealotry is because it's their first and all of the knowledge-based weapons the "enemy" wields are weapons of unknown power. The young zealot only knows he wields the Ultimate Truth, and so any reasoning which confounds or complicates it is unsafe to handle.

A mature, educated person however recognizes that destructive ideology, once given any space to take root, grows, at first in the perifery, until it is too large to easily contain.

So there exist a foolish basis to limit the expression of an idea and a wise one.