They can define it that way if they like. But spiritual to me has a neurological basis. If they want to call what happens in the brains and in communities “spiritual”, they can go ahead. It’s a synonym to me. Misattributed but functionally mostly replacable.
To me, yes words are important but I don’t think they are stable enough to function as building blocks for understanding.
The reason is that words are built upon many layers and levels of abstraction. Some words have strong core meanings and some words are more wobbly. Many words can change their very meaning just by a slight tone of voice shift or even with no voice shift and instead shared background knowledge.