Oh wow, there's crime in an agglomeration of 15 to 16 million inhabitants... no crap! This is not the point though. We're talking frequency, degree of violence, circumstances of those crimes, what it implies for an ordinary citizen walking the streets, and what the situation in New York is like relative to Tehran.
Did you visit emergency wards in an average American city, not to mention South Central Los Angeles or the Bronx? Forget about the USA, it'd suffice to travel to Molenbeek or the northern neighborhoods of Brussels, to the Seine Saint-Denis department outside Paris, to the Croydon, Brent, Hackney, Southward, or Lambeth areas of London, Rinkeby near Stockholm would do as well. Truth is, if you lack the necessary comparative outlook a listing of Tehran hospitals names won't alter the truth.
Namely, that Tehran is immensely safer for a random person compared to any major metropolitan area of the USA. It's apples and oranges, literally.
To even imagine otherwise is to be cut off from reality, so much so that it's no longer funny. I can't say much about the USA other than the fact that it's much worse than Europe in this regard, but I have personally experienced (as in, lived and conducted similar activities in each of these locations) Tehran as well as some of the western European capitals. So when it comes to empirical comparisons I'm rather well placed to speak.
Then again, any person suggesting that Tokyo is as unsafe as New York City, or that it's "the same" everywhere, really shouldn't be commenting on the topic.