I'm usually the one arguing for tags to go away, but in this case, I'd rather see the hackintosh tag stay.
if all posts on the topic are indeed off-topic, the tag will only appear on off-topic posts. If such posts persist in the site, seeng they all have a common theme can help people know what is and is not off-topic
if off-topic posts are naturally deleted over time, the tag will die on its own when no surviving posts remain
our definition of on- and off-topic can change over time, and if posts are tagged as hackintosh, if the site later decides it wants to answer these, the tag marks them as a candidate for potential reopening.
Manually removing the tag from posts on which it belongs strikes me as a bad idea.
I think this is a big enough topic and different enough to include things that may be considered off-topic in AskDifferent, that it warrants it's own StackExchange.
And so, I present my proposal 🎉 Hackintosh Exchange (name pending)
Please come, vote, and contribute to the discussion.