Mostly I'd agree with you, but in this instance DearSA isn't just some petition group. They have quite an excellent track record of stopping shit like this if enough people get involved. Most notable example was a bill that would have regulated hate speech. They stopped it in its tracks. So absolutely yes please pass it on. It will at least give the government pause if they think X amount of people are armed and will not willingly give up their guns.

Look to Venezuela to understand what is going on here. Government wants to start expropriating land and pensions, but too many people still have guns.