He's a leecher though, him uploading 25GB doesn't really matter as the swarm (aka other people) would distribute everything eventually anyways. He could limit the upload to 1KB/s if he wanted to. If he hasn't gotten the full copy yet that means no one has downloaded the entire file. This then means the uploader is limiting their upload speeds or has a bad connection. Which begs the question: why are they uploading?
I read that thread and it seems like it's a seedbox... so why is it slow? The whole point of a seedbox is that it's fast...
Also you're assuming everyone has a bandwidth cap, that isn't the case, and if you had a cap you could limit (while downloading) your upload speed to 1KB/s or whatever, check the torrent every day until the file has a bunch of seeds, then download it and stop seeding once it's done. This is the leecher hit and run style that is not recommended for healthy torrents (although if there are dedicated seeders it doesn't matter much). But you can do it. But on normal torrents (if some time has passed)as a leecher you download a lot faster than you upload. Of course if you get it right at the start it will be limited by the uploaders bandwidth and you have the choice to share (good leecher) or not share (bad leecher).
Anyway, why is that your fear? That shouldn't affect you at all as an uploader because... you're the uploader.
You could just try uploading a torrent and see if it works out or not (that is if you're interested).