I agree that most engineering students don't care much either, but they generally have to put more work in and leave with some practical skills as well as a nice signing bonus + job at the end of the program. Humanities majors can just end up lost, no better off than after high school, and spending their 20s 'exploring.'
Take this with a grain of salt, I recently graduated so these are just my thoughts. Maybe in 10 years when I'm 30 I will say it's better to spend your 20s exploring. But probably not :)
I think there are a couple things happening here. First, "everybody graduates." There has to be a path to graduation for everybody, or the parents, donors, and policy makers get quite annoyed. For this reason, there have to be "fluff" majors at every college.
Second, engineering has always had a public mission that is not shared by the humanities. Employability, and providing a minimal level of skill, are the purpose of engineering. Engineering says: "We will make you employable in spite of yourselves."
The humanities have not adopted that mission, and say: "You will make yourself employable if you take full advantage of what we offer here." You end up with a mixture of students, some are working barely hard enough to graduate, and a few are turning themselves into the next generation of thinkers.
Of course every field wants to sell itself as a gateway to employment: The world still needs "critical thinkers" and all that.
Take this with a grain of salt, I recently graduated so these are just my thoughts. Maybe in 10 years when I'm 30 I will say it's better to spend your 20s exploring. But probably not :)