[grumbling about 1st year philosophy students]
I'm convinced that it is because of how the classes are taught. First, a concept is introduced. The students are expected to understand the arguments. The thing is, the old style philosophers were so paranoid that they make their arguments like fortresses. If you give them ground (i.e. accept their assumptions) then they literally cannot be proven wrong.
The next class period, the students are all excited to find such a smart, well thought out worldview and they are convinced that if everyone would just learn [utilitarianism or whatever 1st year text they've been assigned] then the entire world can get straightened out. They're excited to find out what more the class can possibly teach them.
The professor then proceeds to thoroughly debunk the philosophy, starting with the assumptions and then moving into various contradictions that may arise. The students' worldview is shattered. A new topic is introduced, usually one that was a response to the flawed initial topic. (Old style philosophers also liked to call each other stupid.) Now the 1st year philosophy majors have a brand new concept to latch onto, and the cycle continues.
It's a bit like econ-majors. The intro classes are pretty interesting, and convince students that they know everything about the topic. Why, they ask, have unions been allowed to survive when pure competition is obviously the best thing ever conceived?! Then they take 312 and find out about Monopsony and/or collective bargaining...etc. The problem is that people are way overconfident in what they know, even when there is obviously a body of knowledge they do not yet have.