The votes themselves are the federated action.
If you fetch an old post, your instance will not see the previous voters. After that, whenever a user votes the instance will get the message "User X@instance upvoted/downvoted post Y" and the vote will be added to the database with the voter's user ID and counted.
This has a practical function. If you don't keep a list specifying who voted for what, it would be much easier to fake votes from one instance to another by simply communicating the message "Downvote post Y". With the current method it is still possible to create a lot of fake accounts and mass-vote, but at least you can get a better insight when looking at the database if the votes are associated with accounts with no activity from a single instance.
There are some federated platforms that will show who likes / dislikes something. I know that friendica used to do this - I have not checked if it still does. So it is not only admins who can see this, this is is basically open information in the fediverse.
I don't have much of an opinion on this topic, I haven't really looked into it.
But as soon as I saw this image, the El Al Flight 1862 which crashed in the Bijlmer in Amsterdam in 1992 immediately came to mind. The shape of the hole is very similar!
This image shows the likely position of the Bijlmer plane during the crash:
The image you posted of the Pentagon seems to me consistent with what I have seen of the Bijlmer accident, and so the shape of the hole and the absence of wings in the photo does not persuade me personally that no plane was involved.