Breaking change in practical terms means a change that doesn't break my environment. That's why Microsoft was in a bind. You fixed an issue. Your change obeyed

Breaking change in practical terms means a change that doesn't break my environment. That's why Microsoft was in a bind. You fixed an issue. Your change obeyed all relevant theoretical stuff, but to a consumer it's a breaking change. But customer sees that going from Win X to Win X+1 broke their stuff and they will harass your support.