The HN banner idea would only antagonize the HN folks. In my childhood, parents made me eat tomatoes, because, you know, it's healthy. Since then I despise tomatoes, even though at a rational level I understand that my parents were right.

The techies types are knowledge first people. If you want to win their support, appeal to knowledge, make a rational case, but avoid trying to fool them, as the moment they notice a logical inconsistence in your ideas, they'll dismiss them entirely.

Most activism appeals to emotions, to feelings, because it matters a lot to most people. But techies put dry knowledge first and so needs to change your tactic.

Nevertheless, I'm upvoting your comment because I believe it presents an important viewpoint.