I don't agree that overlapping matches is the only interpretation of "all matches". it very clearly does return all matches and it removes overlap

The post states clearly "finding all leftmost-longest non-overlapping matches without quadratic blowup"

The engines mentioned at the beginning all return nonoverlapping matches. Basic document search returns nonoverlapping matches.

Finding overlapping matches is exotic and rarely ever used in practice outside of network security. It does solve a different problem