The difference, from my perspective, is that the mixing of romantic and work relationships in a poly context has much more widespread damage. In monogamous relationships, the worst that can happened is that there is one incident involving 2 or so people, which can be dealt with in a contained way. In poly relationships, when you have a relationship web spanning a large part of an organization, this can cause very large harm to the company and to potential future employees. I, frankly, would feel very uncomfortable if I was at an organization where most of my coworkers were in a polyamorous relationship.
The difference, from my perspective, is that the mixing of romantic and work relationships in a poly context has much more widespread damage. In monogamous relationships, the worst that can happened is that there is one incident involving 2 or so people, which can be dealt with in a contained way. In poly relationships, when you have a relationship web spanning a large part of an organization, this can cause very large harm to the company and to potential future employees. I, frankly, would feel very uncomfortable if I was at an organization where most of my coworkers were in a polyamorous relationship.