You're both right - the Browns moved to Baltimore, but after legal action a compromise was reached in that the new Baltmore team was not allowed to 'take' the Cleveland team's history and records, meaning the new Ravens essentially had no history and were considered an expansion team. Then what was in reality was a new expansion team in Clevend was technically 'reactivated' as it was allowed to have the history and recorsds of the old Cleveland Browns.
So yeah, it's NFL BS to prevent the Cleveland butthurt but 'technically' and 'officially' the Ravens are the expansion team, but in reality the Ravens are the old Browns and the new Browns are the expansion team. What I can't remember from when it happened is why anyone gave so much if a **** about Cleveland to make such a groundbreaking ruling.