I always spend some time reflecting on my classes once the semester is over. Something I notice in the toleration class is that there are students (seems to be quite a few, although this is anecdotal and I haven't counted them up based on writing or discussion) who hold two positions that disturb me: 1) a belief in ethical relativism (which little understanding or distinction between the subjective or conventional forms) and 2) paying lip service in support of, but having very little respect for free speech. Many of these students want to have it both ways - they insist they are tolerant but at the same time believe in censorship, and they are uncomfortable with examples of relativism's dilemmas (ie, slavery, Nazis, infanticide) but hold fast to the "everything's relative" mantra, personally and/or societally.
Since many of the students in the toleration class are freshmen, I have suspected that they don't really understand the relativism / objectivism debate, are not familiar with the (valid) historical origins of relativism, don't truly comprehend the meaning of political tolerance, and are confused about social and moral tolerance. But even after several classes on the subject, on the midterm some students continue to argue positions they can't logically defend.
Now I do my best to be "vanilla" in my classes. I've never been someone who respects when teachers and professors push their opinions on students. I select the materials and let students make up their own minds. I have to admit, though, that these two positions I detect nearly every semester in at least a few students bother me.
I've read (on the Internet) assertions that this is coming from K-12 schools (and colleges) pushing an agenda. I have a hard time believing that is what is responsible for it. Not that I think agenda-pushing is absent from schools (and higher ed institutions), just that I am not sure how effective it is. Blame is sometimes assigned to teaching multiculturalism and even on classes such as my toleration course. (The latter is amusing and demonstrates the same ignorance these students have with understanding what the word actually means.)
Full disclosure: I support teaching some level of diversity and multiculturalism. However, when I solicit student input on how much multicultural curricula and methods they have experienced, although nearly every student has been exposed, it is limited to food festivals and fairs about an array of individual (and usually non-threatening) cultures. Any sort of deep immersion is very, very rare - practically nonexistent until college, and even there it is usually through solitary electives. Finally - toleration especially but multiculturalism also do not automatically equal ethical relativism and reduced free speech.
So I am not sure that schools (and colleges) can be the primary cause.
I think it has more to do with just general societal attitudes and misunderstanding. It isn't just schools or colleges. It's everywhere, and I believe stronger and more influential in media (for example) than in academe.