It about variety. Changing the speed and pitch songs makes them into a new experience. Don't be like that, the original song is very good of course but this version has a different vibe. It's the same with remixes and cover versions, they're a new way to experience the song.
I know that it can sound bad, not all the songs modified in this way are like that, but I like to do that since it amuses me and I like to do it, if you don't like it, it's fine and you can go listen to something else, it's understood, but every one has preferences so I respect yours and you have to respect others.
