This is probably a reflection of US racism more than anything else. The US-mexico border is constantly in international news so there is an awareness of your ‘challenges’ with migration across that border.
You may conclude that we’re anti immigrant but Australia has double the per-capita immigration of the US. Nearly 30% of our population was born overseas as of 2020.
We didn’t enact a zero tolerance policy for immigrants, and I’m unaware of anything remotely similar.
Hopefully this protest is peaceful, unlike the one during the week where protestors were chanting “gas the Jews”.