It's a bit jarring seeing pictures of NYC before things went to shit with the outbreak. But there's something nice about them. Personally, walking through the desolate streets is oddly relaxing so I like it. The only time streets are usually empty otherwise is when a tropical storm or blizzard hits.
I'm surprised you were able to go inside the Javits Center to charge your phone. But If I had to take a guess, there was probably an event the days you were there. Otherwise, it's closed to the public. And the biggest faux pas tourists commit on the Brooklyn Bridge is posing for pictures on the bike lane. If you go to some of the more poor/not ultra gentrified neighborhoods, you'll see your share of unfit people. Heck, you might spot a few on the subway and the "comic place" you passed by which was probably The Uncommons, a tabletop cafe 3 blocks away from Washington Square Park.
Anyway, it's always interesting to see NY through the eyes of an outsider. Maybe next time you're in town post- COVID-19 outbreak, you can hit up some regular NYC Era haunts including Action Burger, Clinton Hall, Albion Bar, and Drop Off Service.