If my limited and out of date experience is any guide the likelihood of there being any real sensitive secrets when only two documents with such a label were found are very low.
While you’re correct, the classification of them could carry legal ramifications. But whether sensitive or not, they weren’t his to take. They belong to us.
It should be noted that nowhere is it mentioned what the classification level of those documents actually was, or if those were actually documents or just folders or cover sheets that have classification markings, but are not actually classified.
It is quite common to see WWII vintage documents, most often technical manuals, that still have classification markings on them.
As you say, over classification is common, and declassification requires some flunky to make a decision. It’s much easier for them to do nothing, and go back to surfing for porn on their government computers.
But fake newsers rely on the ignorance of the general public as they try to gin up and perpetuate Trump hatred.