If friendly aircraft can't shoot each other, why can friendly AAA shoot aircraft? It's not consistent.
It is consistent. You can't get shot down by
player controlled friendly ack, same as you can't get shot down by friendly planes or GVs. And that had only been implemented in the first place to prevent griefing on a major scale in the MA.
Friendly ack doesn't aim for you but if you get in the way... just like the real thing.
There's an old wartime saying: "There is no such thing as
friendly ack!"