"Canadians voluntarily joined and served beside their brothers and sisters from the United States in all branches of the U.S. armed forces."
Canada didn't send troops, people in Canada left Canada to come to the US and serve the US military. Canada itself did not commit troops.
quib·ble Pronunciation (kwbl)
intr.v. quib·bled, quib·bling, quib·bles
1. To evade the truth or importance of an issue by raising trivial distinctions and objections.
2. To find fault or criticize for petty reasons; cavil.