But to answer your question, if there is a plugin with a torrent client included then it is most likely set up to download the files sequentially to allow streaming but i would assume it is set to turn upload off (so it leeches) because your tv would probably buffer more if it used additional bandwith
If thats the case (not 100%) then that may be why they are trying to block stremio
I'm not so sure that this would hurt those tho. These services would require their to be at least 1 seeder to be able to stream it, so they arent really taking the seeder away. Most likely the seeder dropped.
If anything this would help the seeder by offloading downloading of the show else where and providing a second place for the file. Typically if you see a low seeded content that you like, it would be courteous to seed it after downloading it