What's wrong with childish? If someone is responding to an inherently childish concept ("I know, let's write all our websites with 150Mb of JavaScript rather than using HTML simply and straight-forwardly like it was designed to be used"), sometimes a childishly obscene response is the only appropriate response.
Its not an effective way to frame an argument. Claiming that it is an appropriate response is basically saying that people who write overly complicated websites are so stupid that they cannot understand a reasonable, adult conversation. This is just plain ridiculous. The majority of people who write bloated websites are probably very smart individuals who just need to learn more about design.
