You could hardly drive people to aggressive, angry, nasty, use and abuse other players-type behavior if you tried.
One person needs to take initiative and spawn Infected Manes at the 3 mini mane respawn location. This person can only see 1 of 12 Infected Mane spawns. People who instance hop can freely check the other 11 spots for maximum gains, using the 1 person doing work to reap all the gains. The system is set up to intensely pressure people to first seek out, then use/capitalize on the 1 person doing work for their own benefit. This in-turn trains people who want to spawn manes themselves to become one of the aforementioned leeches, so that they finally stop getting abused and in-turn dish out abuse.
The mental breakdowns and vitriol in zone chat aren't as bad as they used to be, but they're still there. I'm assuming there's some sort of zone chat records you can look back on to confirm just how over-the-top spiteful chain farming makes people.
This part of the Avernus hunt system desperately needs a rework, to either have the Infected Manes spawn separately from little mane kills, or having little manes drop Gore-Covered Chains, or something that stops the core mechanic from being "find an empty instance and pray someone doesn't steal away your hard work-> figure out it's futile and start hunting down newer farmers to steal their hard work." Again, you'd be hard-pressed to find a better way to push players to abuse each other if you tried. Avernus will remain a cesspool of toxicity until something changes, or ribcage stops being the definitive best-in-slot chest for most characters. Another fix would be to release a new chest with the same equipment bonus, to pressure people away from this particular anti-fun anti-community farm.
A thought: if this is all to cause "hell RP" and push people to act/become evil to get their gear, then the chain farm is actually a masterclass move. Don't think that's the case though.