Qn: If a doctor was experimenting with live innocent people for studies, would you praise him or denounce him? What if his studies saved many people?

The answer is that you wouldn't praise him. Probably wouldn't denounce him either. Depends on your thought process/morals/values. To answer your question, think of the doctor as the artist. The doctor's studies as music. The doctor's studies helped many people just like the artist's songs. People would use the studies for further knowledge and songs for themselves.

You don't need to delete the artist's songs. The songs may be good or bad but you just need to accept the better part of both the song and the artist. The artist is not the song. The song is not the artist either. Just keep your conscience clean and that's it.