I will try. I tend to think of "The Celts" linguistically as a set of related languages. However, that is an artefact of my own training and background. How the people who spoke those related languages lived can differ radically wherever you find them. For me, to define Celtic is: did they speak a language that is related to those that we have labelled as Celtic? That means that "Celtic" is a convenient shorthand for talking about these languages and does not necessarily have a meaning outside of that.
I have not yet finished reading the linked article so I will see if it may alter my thinking any.
I have not yet finished reading the linked article so I will see if it may alter my thinking any.