I mean, hardly the same here. Offline content is only available to subscribed users, so it makes sense that it's physically deleted from your computer, but you don't lose it: all your "favorites" are still attached to your account.
I do agree that it's a pain if you rely on offline music, but not re-downloading previously-downloaded content is more of a programming issue than a policy one, unless they specifically do it to save on egress fees.
With their generous freemium program, I don't really fault Spotify here and it's unfair to compare it to HP.
Different terms apply to streamed music vs downloaded music, so offline-caching of music would have required negotiated exemptions from the licensing organizations. They probably had to limit the period of time that a downloaded song could be accessed offline.
If you listen to these songs so much, just buy them. If you're a programmer it should be pocket change for you.