You're answering "why" instead of answering "why not" again. "Why should you lock your door if you don't have anything expensive?"
Plaintext HTTP should not exist, then we wouldn't be having this discussion. I wouldn't have to come up with elaborate scenarios where having HTTPS from the get go would have saved lives, and you wouldn't have to come up with crazy "but that'll never happen" retort to them.
Unfortunately, plaintext HTTP exists, so here we are, with me telling you that the pro-gay rights piece you wrote on your static blog contains keywords that make it be viewed as extremism/terrorism by Russia's automated monitoring systems and anyone reading it gets immediately added to a watchlist. Unfortunately, a few of your readers are from russia and six months later those readers join a political protest against the killing of kittens or something. Their government notices that and makes sure to "take action". And to think HTTPS could have avoided that.