I download them from YouTube. I don’t think that’s illegal (The YouTube video has to be downloaded to my computer in order for my browser to play it. I just go one step ahead and extract the audio as mp3)
You can download a youtube video with youtube-dl and one of the GUI projects that use it, once it's on your drive then you can use Audacity with the ffmpeg plugin to open that video and automatically get only the audio track(s) from it.
In Audacity you can label gaps and after that multi export each song as a batch from that track. In audacity one can resample, edit, export as many different audio containers (mp2, mp3, flac, ogg, etc...)
if i watch a movie in a cinema I will see it, right? I just take one more step and record my movie in the cinema so i can see it later.
also, just because you can see/hear/taste/etc something in a given set of conditions does not mean that you have the right to re-experience it in perpetuity for free.