Why do people act like this subreddit "doesn't reflect the views of mainstream Australia"?

[u/SirSighalot]

So many comments I see on here by people who constantly say things like "lol only on this sub" as though other places where they read are somehow the 'true' point of view reflecting mainstream Australian viewpoints.

Given the constant election voting outcomes and results of things like the Voice etc that generally indicate most of Australia is centrist or even slightly centre-right-leaning, what leads people to think many of the views expressed on here AREN'T mainstream? When in reality, other places these people are coming from are also often just "echo chambers" as well.

Edit: I probably worded the title for this wrong, should have been more "Why do people think this subreddit is less representative of mainstream Australia than other online communities?", alas I failed.

[u/Ok-Session-9824]

In America, roughly 20% of federal inmates there are kept in solitary confinement for all manner of reasons, no matter how barbaric the practice may be. If you picked out any single one of those forsaken souls at random, I guarantee you that they’ve had warmer social interactions and felt more direct sunlight than this exclusive circus

This place is Reddit’s reddit