Here's the exact quote:

"The most stringent protection of free speech would not protect a man in falsely shouting fire in a theatre and causing a panic."

The above does in fact describe a "clear and present" danger. You'll notice, however, that saying anything on the subject of vaccines, a pedophilic cabal in Hollywood, or the Moon landing is in no way like triggering the immediate stampede of desperate people who have no time to consider the truth or falsehood of potentially being trapped in a burning building.

That analogy is simply too often misused. I have to wonder if its misuse isn't itself "misinformation."