>Also, it's not like they maliciously inserted this thing to mine crypto for Norton itself.

No, but it is still malicious in the sense that it:

(1) does not inform the user or ask for consent

(2) seemingly does not offer an option to disable it

While I want to apply Occam's razor here, you'd have to assume all of the people that worked on this were negligent or unqualified... when sadly the more likely scenario is that these decisions were most likely intentional.