You should paraphrase this a bit.
I kind of stopped halfway, but we always perceived thievery as a swing between lawful and chaotic, not good and evil. The things that separated good and evil (for us) was death/torture/rape etc... Theft, etc.. may not be moral, but they were never evil, just chaotic. Our DM never allowed any non-good alignments (except true neutral for druids), so to be a thief (1e mind you), you basically chose CG. We stole when we needed it.
In short, the tipping point between good/evil is morals. The tipping point between law/chaos is social order/laws.
In our games anyways. I think (i say think because it was LOOOONG) I saw sneak atk, and I see this more as a strategic blow. Sneak atk gives some misconceptions as to intention, but I always saw it as you are able to land a deadly blow (achilles heel, jugular, etc...) because you catch the target off guard.
Is it honorable? of course not, but I don't think honor plays into alignment, unless you are in a regulated combat (gladiator match or prescheduled dual) where rules are established prior to beginning. In that case, there are laws (rules) that you would be breaking, and that falls into the category of law/chaos.
My thoughts. I may have missesd the point of the conversation, but again, that is too much for me to read.