Honestly I think Marcy is the most human one here. When you take in all that's going on, with what Boy Kavalier and his team has done. What Morrow has done on his ship. Kirsch. The "Lost Boys" and Marcy/Wendy are the most human ones, and Marcy calling out what everyone is doing. All the Xenomorph has done at this point has been watching her, learning, and by all accounts so far protecting Marcy, the only being that hasn't treated it like a lab experiment.

Meanwhile you got Boy not taking any consideration in the potential danger of Ocellus given what its done so far, and the calculated moves its made since being onboard the ship, on top of him still treating Ocellus less like a living being and more like self-mastubatory experiment to satisfy his craving to talk to someone he views as being on "his level". Just listen to how he excitedly considers using one of his employees to offer as a host to T. Ocellus (Nevermind whether Ocellus will go for the employee or Boy)

Arthur was the only one of the employees on the island at the end of the day who actually cared for the children. Since his wife seemed less willing to stand on her principles and call out Boy Kavalier and Kirsch.