Hi. Copy only works on selections, and your scope would need to be narrowed, unless there’s only one matching label per document, as selections don’t cross pages. I think this example may work to answer your question, but your version has some differences from mine and the question is probably not the right one; there is rarely ever a compelling reason to use a selection for anything other than testing, as they are inefficient GUI processes.
I have a single page with 10 items with individual tags, I need them in the pasteboard as I’m doing a GREP search, replacing with the contents of the pasteboard – in this case an anchored object.