Not really. The information is public. Even if the app hides it, attackers can download it from a relay.
Let's hope listr.lol starts creating private follows. If that comes to reality, Amethyst will be using the private part of those lists as well.
nostr:npub1zuuajd7u3sx8xu92yav9jwxpr839cs0kc3q6t56vd5u9q033xmhsk6c2uc