"Arguments over grammar and style are often as fierce as those over IBM versus Mac, and as fruitless as Coke versus Pepsi and boxers versus briefs"

This quote by Jack Lynch is comparing the intensity of arguments over grammar and style to those of other popular disputes. He is recommending that arguments over grammar and style can be simply as passionate and heated as debates over IBM versus Mac, Coke versus Pepsi, and fighters versus briefs. He is also indicating that these arguments are eventually unsuccessful, as there is no clear winner in any of these debates. This quote is a humorous method of highlighting the truth that arguments over grammar and style can be simply as extreme as other popular arguments, but ultimately, there is no right or incorrect answer. It is a tip that everybody has their own viewpoint and preferences, which it is very important to appreciate the viewpoints of others.