I wouldn’t call them leechers since they are seeding back to build said ratio. I think it’d be more accurate to call them a single component of a larger ‘structure’ including people like myself who permaseed from home on a slower connection. If it were all people like me, we’d all be waiting days for new releases to fully download and if it were all seedboxes, we would have zero seeders for anything older than a month or two. Many private trackers incentivize long-term seeding to help control this imbalance, and I think it works well in my experience.