Ransomware as define by Kaspersky:
Ransomware is a type of malware that severely restricts access to a computer, device or file until a ransom is paid by the user.
Link:
https://forums.androidcentral.com/e...ter%2Fdefinitions%2Fransomware&token=1u_FcmB8
Somewhat paraphrased by PCMag:
Virus software that blackmails users by encrypting their hard drives or locking them out of the computer. It then demands payment to restore it.
Link:
ransomware Definition from PC Magazine Encyclopedia
Your access isn't restricted, or encrypted. Really, the knock knock feature is a signed feature by LG that is mimicked by other programs. This isn't too dissimilar from not being able to use some Samsung widgets while using Nova.
As of right now, there are two choices; pay the upgraded version of Nova, or, use LG's stock launcher. To a degree, Yoda said it best; 'Do or do not'.
To reiterate, you can get Google Play rewards app and build enough credit to have Google pay Nova's Prime app for you.