I appreciate the support guys, but this is just trolling. Whether this poster was serious or not, he didn't have enough information to make this judgement and he did, emphatically. Classic trolling.
So for promoting bands on social media, what I would is provide interesting content to the broader audience, like if we made a cool youtube video, and then be sure people knew where to find information about shows, I.E. the event pages for those shows.
However, I did creep into the world of spam from time to time: I would post unsolicited posts on my friends walls about really important shows. However, I did this very carefully, posting it only on my friends walls who I KNEW were strong supporters and wouldn't mind. This increased visibility without annoying anyone too much.
But it was kind of spammy and I'm not here to defend myself on how I promoted local art and made a living. I think spam comes down to intentions and being open to feedback: if you don't want to see my messages anymore, I would stop sending them to you IMMEDIATELY, including sending you event invites , and excluding individuals from those used to be really hard.