Chordify automatically extracts chords from songs. Unlike lyrics or melody, chord progressions are not considered innovative or sufficiently unique enough to be copyrighted on their own. In fact, some chord progressions are particularly popular and are used in exactly the same shape by hundreds of popular songs!
In any case, copyright owners who do not want the chords of their works to be displayed by Chordify can request the retraction of individual songs by emailing retract@chordify.net.