That begs the question though, should it be? If you’re looking up the lyrics to a song you’ve bought, does it really matter, at least philosophically,
how one retrieves them?
What you can't do is distribute the lyrics without the author's permission.
When you ask DeepSeek to retrieve the lyrics (and it does so), the real question is this: Is DeepSeek merely acting as an intermediary/ISP according to the DMCA (in which case they'd be protected under the safe harbor clauses) or are they illegally redistributing the lyrics without the author's permission?
Whether or not you own a copy of the lyrics is irrelevant from a legal perspective in this scenario.
My guess: If they just retrieved the lyrics from some website and delivered them to you (because you asked), they're an ISP. However, if they pulled them out of their own database, they're violating copyright.