I HAD A BIG LONG META SPIEL HERE but I don't think it's true any more so I'm just going to leave the bits I translated:

(These are mostly my translations. [Brackets] are a more literal translation while stuff outside of brackets is closer to a localization.)

F/A, EP 14

Avicebron: But I hate humans, and I am a pessimist. I wear this mask because even seeing eye-to-eye to another person [meeting another person's gaze] is troublesome. So, why did you believe I would never make arrangements to abandon you?

F/GO, Lostbelt 1, chapter 13.2

Mashu: Avicebron-san, you must really like golems.
Avicebron: No, it's simply that I hate humans.
Mashu: Eh
Guda: Eh
Avicebron: ... aah, that is not to say I abhor them. I see, saying it that way might give the wrong impression. I find being around other people troublesome, and want to avoid it. That is simply my nature [personality].
Guda: But you're speaking with us now ... ?
Avicebron: Upon becoming a servant, I've seen it as something I should try to rectify. I wish to continue conversing, even though it may be troublesome.
Mashu: But if it makes you uncomfortable, we should also refrain --
Avicebron: No, that would not do [is not good]. That would absolutely not do, Mashu. I hate humans. Even so, I strived to save humans. Both during my life, and afterwards. ... it would not do, if my reasons for doing so were to remain ambiguous. It would not do for the giant, which should be indestructible, to be fellable. If, despite that, it became fellable, then it is my fault [I am in the wrong].
Mashu: Avicebron-san?
Avicebron: ... excuse me. I spoke too much. [I lost control of myself.] Regardless, I feel I'm close to grasping something. For that reason, I should continue to converse with you. So, do not worry about my feelings. I wish for you to speak as you always do.