It's a widely discussed, easily understood, and thus popular yardstick, both among economists and the general public. I think you know this quite well. This isn't high school debate club and barking orders at people like 'define fairly' isn't clever, just rude.
So you've decided to unilaterally determine my intent and tone, appoint yourself the arbiter of behavior, and inject yourself into a conversation to double down on your incorrect stance (from Wikipedia: "Due to the flexible nature of the term 'needs', there is not one universally accepted measure of what a living wage is...") and lecture me about rudeness?
I'll pass on continuing this conversation, thanks.
Please don't jump into conversations and chastise people for no reason, especially when you're incorrect.