Did you miss the part in bold or just conveniently ignore it.
When I wrote it, it was connected in my mind with the previous material concerning your workplace. My apologies for that confusion.
However, let me add this: even when they are uncomfortable, a lot of people will say "Hi" back to you, in the hopes that you will then not say anything more. So, the mere fact that you have gotten "Hi" back does not mean that your utterance was welcome.
Or perhaps just answer this straight up:
Is it wrong for an individual to approach another individual and attempt to engage them in conversation, or simply greet them potentially habitually, by saying "hi"?
Sorry, but I don't have a simple "yes" or "no". In fact, in your text below, you make it clear that you do not, either, or you would not bother to list some exceptions.
Actions have consequences, sometimes unintended consequences. Ethical people consider the consequences of their actions, and accept them even when things go wrong. I'm not your teacher, your prophet, your holy book, or Miss Manners. Every interaction is different, and there are at best general guidelines and considerations, but no hard-and-fast rule.
And it cannot be a "yes....if it makes their day worse" or "yes as long as you understand it is your fault for interrupting their day" or any esoteric crap like that. We are talking basic human interaction here. We can infer lots from what you say and you always have another reason to shift what you are implying. It's like trying to stab a marble. Lay your opinion on the line. Here I can start.
My opinion is that it is absolutely socially acceptable to approach another individual absent of all signals or cues and say "hi" to attempt to initiate a social interaction regardless of their ultimate response.
I will give one caveat that it would not be acceptable in the face of crazy obvious cues (people running, someone hysterical, maybe she lost her baby or something, people already engaged in conversation, person actual says out loud "no one talk to me", person is huddled up in a corner and staring at the wall, people on the phone, people with their headset on and jammin to their fav tunes, people reading, etc.). But I still hold that the act itself is perfectly acceptable in all but the most extreme cases.
My personal standard is that I don't talk to people (on the bus/train, walking in the street, etc.) unless I am fairly sure my conversation will be welcome, and I don't just assume my conversation is welcome.