- "Violent crime is more common in the US than in Australia"
- "Medical costs in the US are extremely high. You may need to pay up-front for medical assistance"
I think some Americans don't realize that, outside of America, many people don't ever consider the risk of gun violence in their day-to-day lives, or owing thousands of dollars for visiting a hospital.
As for the medical costs - if you want to be on the safe side, you can (actually you should) get travel health insurance.
You have to read your insurance contract and info sheet properly rather than go for the lowest price.
Though you might need to get a US specific one. Mine contains a clause that specifically excludes the USA from coverage, and that’s not uncommon.
Note I live in London and everyone tells me I'm going to get stabbed too and die from the pollution...
That's an 0.006% chance of getting murdered killed in NY every year.
And that doesn't account for (a) putting yourself in a good position to get killed like being a gang member and (b) the aggregate reduction in risk by only travelling there.
Quite a few people don't want to deal with that.
Most of the world sees the United States as a dangerous country.
For example, using the source you've just given, the US homicide rate is over 5 times the homicide rate of the United Kingdom, France and Germany, and over 10 times that of Norway.
Granted, you're more likely to die in a car accident than to be murdered in the US, but that's no reassurance; this is partly because the vehicle accident mortality rate is so high in the US, at over four times the rate in the UK. And your comment about dying in a plane crash is completely wrong: the air travel mortality rate is very close to zero, with under 200 deaths for over 800 annual million air travellers; a rate of less than 0.025 per 100,000 per annum.