> Over the years I've found writing on HackerNews, Reddit and other online sites has given me an outlet to get creative and engage with folks in a way that will shift discourse towards something I'm more interested in.

Have you tried looking for communities for creative writing? There are places (including reddit) that post/accept writing prompts which spawn some discussion. You can do what you do, write fiction, get some engagement about the topic and be upfront about making it all up.