It also reads as someone who understands the pronoun issue, but doesn't understand the temporal rules around pronouns. Instead, just opting for the traditional gender-neutral pronoun.
There's a lot of different perspectives and opinions, and honestly the rules aren't clear cut yet. At this point I pretty much always refer to people as "them" online.
That's a valid interpretation, but it's based on assumptions. Personally I didn't even notice the use of "they" vs "he" or "she" since it's not really relevant to the discussion. In fact, OP has clarified that he/she used "they" only because they were unsure if gender changes apply retroactively since at the time of the leaks, manning identified as a "he"
It is not other people's responsibility to know what your preferred pronoun is; you don't have a right to a preferred pronoun; you don't get to tell other people how they should speak. They is perfectly appropriate in all situations as it is gender neutral.
There's a lot of different perspectives and opinions, and honestly the rules aren't clear cut yet. At this point I pretty much always refer to people as "them" online.