Shanghai sucks. Even if there was no Attack chopper, this map must have been full of roof campers. This map is bad for every mode.
It's not the map that's so bad, it's the player mentality -
1. Players go camp on the roof
2. Chopper comes along and kills them
3. Players respawn then go back to the same rooftop they were just killed
4. Chopper comes along and kills them
5. Players respawn (only 1 of them equips a stinger/igla) and they return to the same rooftop
6. Chopper comes along, player shoots stinger at them, chopper runs away but knows where you're at, thus maneuvering into position for his gunner to be able to take you out from a distance. Rooftop campers all die again
7. Players respawn (again, only 1 has a stinger/igla) but this time they find a different roof
8. Repeat step 6
9. Players respawn and return to roof #1
10. Repeat step 6
11. Game ends or the players rage quit
Moral of the story - if you're going to camp on the roof, accept the fact that you are going to get farmed (and don't cry about it for 10 years like Sirlin has done.) Accept the fact you are bad.
TL;DR - The definition of insanity
battlefield stupidity- doing the same dumb things that get you farmed but expecting different results.