It's a poor metaphor. Real tolerance necessitates intolerance - see Marcuse. What is a browser going to do, send malformed HTTP requests and name-and-shame any server who refuses to respond? Servers vs. browsers is not the same type of relationship as people vs. people.

Not to mention that the author's metaphor is implying that certain types of people are malformed.

I understand what the author is trying to say, and I agree with the second half of the text, but the link between both halves is tenuous at best.

They are saying the logical structure is ill-formed.