I think you could argue teenagers have a right to discuss political issues in the public forum. That's basically the definition of good citizenship, and (for better or worse) social media is the public forum of the day. Kids don't go from zero rights at 17 to full rights at 18; minors' rights are limited, but they do have rights.
I dunno if that'd fly in Australian courts though.
Well kids can discuss political issues across other discussion boards just not those on the social media sites impacted by the ban. They can also continue to do it say, in person in public.
I think the discussion of political issues in a sensible way on platforms like instagram, tiktok, X, Reddit etc for those ages is perhaps a lower priority than the mental health impacts that those platforms in general provide.
Interesting to frame this as a bad thing. As a parent, I would take that as a feature, not a bug. To me this is very suspicious why there seem to be so many people here, who I am assuming are mostly adults, advocating so strongly strongly for <16 olds told be on social media, as if it was something they need.
Kids not being able to do particular things until they're of age? That's much of an egregious violation of their civil rights.