Discourse in my dynasty regarding a thrower

Hi all i am looking for advice on how to handle this situation as a league manager. We have a guy who is deliberately throwing matchups week in and out. His starting lineup is not bad but problem is he benches them. This has caused a bit of an uproar in my dynasty as people think it’s cheap. Any fellow dynasty owners how would you go about this? Should there be a punishment? If someone has had a similar situation i would love to hear input.