Solarpunk can be both cultural, as in sci-fi worldbuilding, and activist, as in our individual everyday actions (I agree with the excellent comment from @LilNaib about the individual power we have - activist work should not leave people frustrated of even burnt-out). The activist part is the foundation of the worldbuilding ('How would the future look if people worked towards what I work towards'), and the worldbuilding part is the foundation of the activist work ('How do I want a better future to be like').

It's very tough to try to convince others of solarpunk, or anything, by commenting or posting online. Convincing happens, if at all, really slowly, by example rather than preaching. It can take generations. Right now we are a very sick society, slowly becoming self-aware, and if we manage to point ourselves into a good direction, we might live in a better future. But we cannot be this future now, or expect others to be this future now, it will take time.