A true hero is someone of great courage and ability. A hero is someone who has influenced someone's life. He/she is a role model to a person.
In the story "India's Heroes", Kabeer seems to be greatly influenced by the great people who sacrificed their lives (on 26th November 2008) so that we can have a better future. All the people mentioned, are a role model to someone ( Here, Kabeer) which makes them true heroes. This is heroism. Thus, this story brings out the meaning of true heroism.
Yes, Real heroism often goes unacknowledged. In this world people judge a person only by their looks and their physical appearence and not by who they are at heart.