Regardless of whether or not social media advocacy is effective in changing people's minds, what I find interesting about the casual dismissal of online political activism is who's most prone to doing the dismissing. Have you ever noticed what kinds of people are the most contemptuous of politics on Facebook?
Everybody wants to feel seen by the person they navigate life with, and that demands that they see your struggle, too. They'll never see it lucidly, though, because they'll never be in your human suit. But it's their responsibility to try to get as close as they can, and to be on your side whether they understand it or not.