Whilst you are correct, and every conflict has blue on blue engagements, the US military have a very bad reputation for being bloody dangerous to their allies.
Mission videos that do emerge of incidents where US aircraft, helicopters and drones end up engaging friendly or non-hostile targets commonly show a marked desire to engage the enemy and view any and all information coming in as confirming that initial prejudice.
I'm not saying this applies to all US military personnel or that other militaries do not have problems.