As someone who wouldn't use this to spread terabytes of pirated media to others, could this hypothetically be used to spread terabytes of pirated media to others?
Well, theoretically then, it's not made to handle terabytes in terabyte chunks (as when you share, someone else is needed to have something to share roughly the same size), it's more thought for megabyte chunks of stuff, like a website. Downloading/uploading would be hasardous too for a TB chunk as most people only have megabit speed internet.
So it's not that it isn't possible, but you would probably have to chunk up any (legal) data in say 1GB chunks, so that your chunks get shared. If everyone shares 1GB videos of their holidays (for example), it would work easily because your chunks would have people needing to share them.
Yes I'm not advocating for illegal things (but thanks for pointing it out), I advocate for decentralised data sharing, for example your website, a personal-"book" (a crude script for that already exists), a chat (exists, also very crude), share some file without uploading it to google or amazon etc etc etc.