Many today consider studying philosophy to be a useless exercise akin to the punishment Paul Newman received in the movie Cool Hand Luke: dig a hole, fill it in, repeat. Many inside and outside the church consider the study of philosophy to be a waste of time, or even worse, a source of deception.
That there have been false, dangerous philosophies is a given. In fact, that is the very reason why we need to study philosophy. For example, the following passage is from Gilson’s history of philosophy, The Unity Of Philosophical Experience:
The immediate philosophical antecedents of Communism were exactly those described by Engels. Lennin himself endoresed the view of Engels, when he quoted German philosophy, English political economy and French socialism as the three sources and the three constituent parts of Marxism. The philosophical source itself, the only one with which we are now dealing, Lenin describes as “the system of Hegel, which has led in its turn to the materialism of Feuerbach.” . . . The agreement is complete between the testimony of the founders and leaders of Communism and the evidence of historical facts. (p.229-30)
Thus we have the founders of Communism and the historians of philosophy in agreement, that the philosophy of men like Hegel and Feuerbach were picked up by political philosophers Marx and Engels, who in turn were followed by Lennin, Stalin, and Mao. These last three men were responsible for mass slaughter, all inspired by Communistic class struggle.
Marx and Engels research began in the dusty halls of the British Library. But what the philosophers began in the ivory towers did not stay there, but was ultimately put into shoe leather by the political leaders. Lennin, Stalin, and Mao were responsible for the deaths of untold millions of people, all in the name of a purely material, religion-less class struggle which was inspired by the ideas of Hegel and Feuerbach.
Thus ideas have consequences. If Christian thinkers had risen to the occasion at the time the original philosophers published their bad ideas, perhaps their teachings would have been rejected instead of propagated.