They are not sharing cybersecurity purposes, they are sharing cyber threat intelligence. Cyber threat intelligence is who is misappropriating government information, intellectual property, what they are releasing, what have you. They are using cybersecurity systems to ensure cybersecurity purposes.
'(5) Cybersecurity system.--The term `cybersecurity
system' means a system designed or employed to ensure the
integrity, confidentiality, or availability of, or safeguard, a
system or network, including protecting a system or network
from-
(A) efforts to degrade, disrupt, or destroy such
system or network; or
(B) theft or misappropriation of private or
government information, intellectual property, or
personally identifiable information.'
Government information is not a virus and it's not stealing someone's IP. To protect a system from misappropriation of government information, one has to edit it or remove it. You are the one making jumps, misappropriation of information is nowhere near the ledge of stealing someone's IP.