We hear so much in certain sectors of the press about how "illiberalism" is overwhelming free speech, but if this chart is to be believed it's a very selective intolerance, counterbalanced by a greater tolerance of speech in other respects.
It does make you wonder what those centrist liberal sorts are stuck on, mentally, when they obsess over the threat to free speech posed by teenagers at Oberlin College or whatever.
The above chart is particularly fascinating: it depicts both liberals and conservatives becoming more favorable to free speech in recent years, including racism. But the closer to the center you get, the less enthusiasm there is for free speech in general and for racism in particular.
It gives me a sense of a relatively small island of elite or establishment opinions where bickering between two barely-distinguishable poles -- the moderately progressive vs the centrist moderates, if you like -- continues to dominate discussion among pundits and opinion writers while the whole house comes down around it.
The far right will occupy the ruins first thanks to Trump and the cooperation of the GOP and finger-chewing moderates, making the surge of racism more alarming. In the long run, though, I suspect that "political correctness" was the most liberal form of selective intolerance that racists could have hoped for, and they will eventually beg for it.