I concur, lucky escape for you. I don't think it's a problem if someone is scared of needles, or uncomfortable around them, but if they were rude enough to make a scene and say "eww" that's not the kind of person I want to know.
I think
@Postitnote is right though, and consideration works both ways. I do my insulin at the table and usually can do it without anyone seeing. But if this isn't avoidable, like maybe a circular table where the person next to me can see my stomach, I would warn them that I have to have an injection so that they can look away if they don't want to see it. My experience is that most people are fascinated and want to watch