I don't do web development or design, but is tracking the selection of text that will be copied more difficult that tracking clicks in actual practice?
Yes, clicking a button or link will send a request to the server with some information in the header, such as which browser clicked from which IP.
Selecting the text will trigger no such request, the developer will still know who opened the site and searched for what, but he cannot know the exact torrent that was copied.
clicking a magnet link wont fire a request to the server.
yes you can track who clicked a magnet link with javascript but you can track who selected the text with javascript also.
The magnet links can be in the page, and downloads and copy/paste UX can be achieved via JS just the same as server-backed as far as the end-user is concerned. This way the entire execution of the page can be audited.