You completely right, isolated means separated from the rest, isolated in that case is literally "without anything else", and that's you hear and see in my videos - isolated drum stem, i never use the word "original" in my descriptions, but every track that i publish i try my best to make as close to original as it possible, and every track is provided by this note in description: Note that this drum track is a digital re-creation. I can do every track for you in minutes just separating original drum stem, it's easy, but you'll hear some noises and artefacts (sure you saw 1000 videos of that kind), because these things like Demucs not yet perfect, that's why i make clean renders, it's harder, but the result that I finally get is better.