I hate how when tragedies like school shootings or 9/11 are brought up, there are people who take those numbers and compare them to places like Africa. No matter how many people died, it's still a tragedy. I think what goes on in Africa is horrible, but that doesn't mean we shouldn't care about terrorist attacks in other countries. When I was in Australia, they brought up on the news that there was an attack in Indonesia and 90 (?) Australians were killed. I don't think that should be considered less important just because "only" 90 people were killed. It's horrible that London was attacked too. I don't think 9/11 should get less compassion because it happened in the USA or because of the number of people who died.
I do agree that families shouldn't be complaining about support though, because I think they got a lot of support. My mom's friend lost their son in 9/11, and she and her husband used to get sent checks for thousands of dollars all the time. Of course, they'd rather have their son though.