Last week's jailing of an Islamic man for collecting and spreading vile images of Isis killings will have fanned a few fires on the subject of immigration.
I include my own kneejerk response, because we're not all perfect.
That's how easy it can be to change a country's course in history, as Britain - is it still Great? - has just demonstrated.
When people are told what they're not allowed to think, it doesn't just go away; it festers.
The rift between intellectuals, city dwellers, and people in the provinces can be vast, here as well as in Britain, and finger-wagging does no good.
It's not just other ethnicities and genders we have to accept, but the point of view of everyone who balks at new ideas, and resents being patronised. You can pass laws, but you can't make people like them, and now we've seen the danger in giving alienated people power they never felt they had. I'm right off plebiscites.
Immigration is a bit scary; it involves people with different languages, beliefs and customs, sometimes arriving in great numbers, and also change, which is scary in itself.
Looking back to the dawn raids on Pacific Island overstayers during the Muldoon era, our record has been every bit as lousy as Australia's, and that is why Imran Patel, the 26-year-old Isis advocate jailed last week, is dangerous.
People like him fan fires that should never be lit. Brexit has done the same, with racism and xenophobia now unleashed on hapless foreigners in Britain.
I won't be the only one wondering how Patel got to live in this quiet, safe country, so far from the violence he so admires, whether or not he shared his bloodthirsty beliefs with immigration officers, and why we can't send him back when he's served his sentence.
But the buck stops with him and Niroshan Nawarajan, 27, also sentenced on similar terrorism charges last week. Blame falls on them, not an entire Islamic community.
Like Patel, Nawarajan harboured grisly images of people being beheaded, shot, and burned alive.
What they get out of watching such sick sadism is worrying. Like sexual porn it seems that violence porn can be addictive and mind-altering, eroding respect for other human beings.
Nawarajan entered the United States consulate in Auckland asking if the building was bomb proof, and Americans don't find that sort of thing even mildly amusing, as anyone who has passed through their airport immigration system will know. Neither should we. The world is too complicated.
It must be so much more complicated, though, for immigrants and refugees who arrive here to safety, then have to build new lives from nothing. We have no choice but to engage with them. Immigration is shaping up as the big issue of our time, with more displaced people, 65 million according to the United Nations, than there were at the end of World War II. That reality, and the fear it generates, is already reshaping the world as we knew it.
It's crazy to imagine you can effectively build a new Hadrian's Wall between Scotland and England, build a fence to keep Mexicans out, endlessly turn shiploads of desperate people away from your coastline, or that you're so far away from the rest of the world that nothing bad there will touch you, because it will.
- Rosemary McLeod is a journalist and author.