What is something that people think is dangerous but in reality is completely harmless?

There are certanly a lot of very not nice places in the city. You probably don't want to be walking around them after midnight, but there is also no reason to be in these places at night as a visitor.

The downtown area is relatively safe (some recent gun clown activity in nightlife areas but it's the USA after all) and populated.

The city has come a long way since the bankruptcy in 2013. It had been struggling for decades before this too. Industry and population leaving the city for the suburbs. The stereotype comes from this and it's hard to move on from because the city stil hasn't even though it's made some big steps.

It's not a perfect city but having basic street smarts you would use in any other city will keep you out of trouble.