They usually have terms and conditions to make it YOUR FAULT if you publish something that has copyright, and they have paid loads of legal fees after-the-event for stolen books in their training data. It's never been fair use, just very wealthy people getting away with criminal acts.
Lovable have the following terms, for example - "You assume full responsibility for your use of AI Output and agree not to rely on it for critical or high-risk functions (including medical, legal, financial, or safety-related purposes) without appropriate safeguards. AI Output may be similar or identical to content generated for other users who submit similar prompts. We do not guarantee that AI Output will be unique, free of third-party rights, accurate, suitable for any particular purpose, or that it will build, repair, complete, or improve any application or project or achieve any particular result."