You fail to take in to account the Eternal September effect.[1] Some people are aware, but others are not because they're new (or for various other reasons, such as just beginning to get interested, etc), and new people will always be coming along.
Also, some people might know but might have forgotten or had their attention shifted to something else. It's good to periodically bring it back.
There will always, always be a need to inform people. Providing information and good/better arguments for one's position will always be a valid and valuable service.
Acting constructively on that information is also needed, of course, but they're not mutually exclusive.
[1] - https://en.wikipedia.org/wiki/Eternal_september