The entire series emphasizes that the aliens made a very grave mistake in initially classifying humanity as a potential livestock species, only correcting this mistake at the very last minute. Seeing that this is an extremely egregious, almost inexcusable mistake, how many other potentially sapient species have they snacked on, not realizing that they would have otherwise qualified for full rights instead? Especially since it's made clear that developing a language and even a somewhat developed civilization isn't good enough by her society's standards.
Further confirmed in part 14, and the spinoff video with Eravin reveals that this is actually a major point of contention between herbivores and carnivores, as the former often harbor the sentiment that the standards are probably too high thanks to carnivore lobbying.
The scene where Subject 50499-A attempts a heroic sacrifice to save the rest of the crew when Ackt is having a feral episode. Earlier they told Ackt that they had low self esteem, and outright told Victoria that they were suicidal before being taken onto the ship. By then, the entire crew hypothesizes that something about the human test subjects is turning Ackt feral, which would obviously make them feel worse about themselves when they see Ackt, their love interest, in severe emotional, mental, and even physical pain because of their mere presence, and it was further exacerbated by them demanding mouthplay from her. So feeding themself to Ackt was not only a desperate move to ensure the rest of the crew survive, it was also a convenient way to commit suicide, believing that Ackt would be better off without them in her life.
The part where Ackt locks herself in the same cell that the Subject 50499-A was confined in. It wasn't just Ackt getting the same idea as Zed and realizing that she could be successfully contained in there until she could receive proper help. It's likely a reflection of how she saw herself. While her horror at her own feral behavior didn't help, she felt inadequate because of her fears that she falls into the uncanny valley and outright tells Subject 50499-A that she doesn't like herself anymore and wishes that she could be more human. Of course, the medical cell is where unknown species are confined until they can be classified correctly, mostly for nonsapient, or semi-sapient creatures. She sees herself as an animal, and thus decides to confine herself to a pen reserved for them.
Hiboritch's attempt to talk to Subject 50499-A in English for the first time is put into perspective in the prequel. Not even he is able to resist laughing about Tori's abduction. When both Acktreal and Caridal eventually come to the opposite conclusion they have had for the longest time (humanity is a potential livestock species), no doubt he felt horrible about this. His attempt to communicate to Subject 50499-A was an awkward attempt at an apology. He probably couldn't even bear to talk to Tori directly.
Later on, Ackt mentions to Subject 50499-A that the herbivore species are incredibly upset at how poorly humanity's initial classification went. Hiboritch wouldn't have been a whole lot different.
