As far as I can tell it's not so much that they suddenly disagree with that statement, rather it's that after hearing about "free speech" and "I'm a free speech

As far as I can tell it's not so much that they suddenly disagree with that statement, rather it's that after hearing about "free speech" and "I'm a free speech absolutist" the cognitive dissonance is hard to bear. Almost like the people who cry for that aren't actually interested in free speech, but rather only wanted to be in control themselves...