It refers to the practice of changing the conversation (often towards accusation of hypocrisy) rather than answering a claim. Especially when the comparison is

It refers to the practice of changing the conversation (often towards accusation of hypocrisy) rather than answering a claim. Especially when the comparison is different in kind or scope, or just plain irrelevant. Making comparisons is valid, but it doesn't make you incapable of responding to the original arguments.