[gochi]

The book Open Society and its Enemies is moreso about how an open society cannot truly be tolerant, much in the same way that Herbert Marcuse expresses, in that tolerating dangerous ideas allows them to grow thereby destroying the entire concept of an open tolerant society. It was not specifically about opposition of free speech, that's absurd as even he would recognize that you can't protect free speech from dangerous ideas without being intolerant of those ideas. Hence, the paradox.

So people shouting their enemies aren't doing the opposite of what Popper suggests, they are proof of what he claims. Remember, he viewed socialism as a beautiful dream, but struggled to align that with his views on individual freedom and how reaching such goal would be very difficult without violent means of overthrowing the status quo (these means again infringing on his beliefs of individual freedom).

Perhaps you are due for a re-reading of his work.