Earlier quoted context omitted.
I don't know what Chelsea Manning's pronoun preferences are, but I have plenty of friends who prefer "they," which also happens to be the gender-neutral singular pronoun in English. For example: "Someone came by asking for me earlier? Did they give you a name?" Many people who do not identify as male or female prefer "they."
That's a valid point, but if you don't know enough about Chelsea Manning's recent history or prison sentence to know her preferred pronoun (or even read the article where it's made very clear) why even comment?
Since I don't know Chelsea personally, and because they're also in what must be a deeply traumatic and confusing situation, replete with pressure to conform to newly acceptable narratives of transition like "man becomes woman," I think I instinctively wanted to use "they" in acknowledgment that we probably can't know for sure what would make them comfortable and happy from our present vantage, news reports aside. If I for some reason meet them one day, I'll be sure to confirm with them what they prefer.