If you’re paying to provide a free server, and along comes another server owner who wants to peer with you. Only they’re charging their users for the same thing you’re giving away for free. Why wouldn’t you be a little bit miffed that they want to take your freely-given service and sell it to their users - because that’s what would be happening in that situation.
Monetising something that’s intended to be free is very, very difficult. Not impossible (see open source software and the businesses that grow around that), but it’s a lot harder when it’s a service.