Why is Henry Pelham's famous picture of the Boston Massacre considered propaganda?

paul reverie had an engraving about the Boston massacre.

he used Propaganda to convince the people that he civilians were defensless.

1. a citizen has his back turned

2. there is a puppy in front of the civilians symbolizing their helplessness.

3. a church behind the battle showing that maybe the soldiers had no regard for religon or church. since they killed people in the presence of a church building.

4. A a building behing the soldiers it says "butchers market" is right above the soldiers referring that it was a slaugter.

it all tries to give the idea that the soldiers committed a haneous crime.