Luis, you said it all in your summary or conclusion.
Like BsAs there are some places where crime is more prevalant than others . It is for prevention that you see the signs. Is there crime? Naturally, like in every big city. But again like BsAs - before it was not, much but have increased because of certain factors.
Thousands of people live a wonderful quality of live there, with small children and they are happy.
Then there are those that don't like it and move else where. It is a personal choice you have to make yourself.
You, coming from a place of change, will understand and adapt easier than people coming from a stable, peaceful, almost crime free area.
Just live in awareness and you will love it I am sure.