Why isn't Thor or Hulk or Hawkeye there? Just have to accept the solo movies are compartmentalized.
Hawkeye was probably off on some mission, but that is a handwave. But Thor and Tony make sense. Tony deep sixed all of his suits in Iron Man 3, so even if he was made aware of the stuff happening, what could he do. 90% of the on street stuff was orchestrated by Hydra under the guise of police activity and likely kept hush hush.
For Thor, he is not the most networked individual, and he swore at the end of Thor 2 to protect the 9 realms, so who is to say he was even on Earth at the time. In every Agents of Shield episode where it comes up, they make a point to say that he if off the grid/unavailable.