Reply: Its really important to put that anger into some kind of constructive action in attempt to prevent the same thing happening next year.
Gather what information you can, research the facts about Canada Geese and then contact proper authorities. Try to find and network with others who are as distraught about this kind of undercover, insidious carnage as you are. Try to find any sympathetic reporters. If necessary (and it sounds like it is) try and organize protests.
Canada Geese are doomed if they do (migrate) and doomed if they don't.
We either accuse them of being murderers (by colliding with planes) or "pests" if they remain in a park or golf course.
But, as you note, we introduced geese to many of our areas in the first place -- mainly as targets for hunters' guns.
The fact Canada Geese have managed to endure and even thrive despite all our attempts to harass them (with dogs), shoot them, or round-up (when they are completely defenseless) and gas, is testament to their extraordinary parental, communicational, organizational and adaptational skills.
Indeed, the Canada Goose's greatest enemy is human.
We nurture and gain their trust, only to ultimately betray them.
Sad statement about our own species, but certainly a tribute to theirs. -- PCA