Stick mixing - throttle?

I’ve tested using stick mixing in Auto as a safety mechanism to avoid birds that might pop up in the pattern. However, it seems in my limited real-world experience and more expansive SITL trials that the throttle does not moderate based on the stick mixing inputs until you approach the FBW min/max. Is there a reason for this?

I’d like to be able to have the FC continue to try and maintain the trim AS (within its abilities giving throttle slewing etc.) this would allow for safer avoidance maneuvers, and the ability to manipulate the aircraft for test purposes and hold airspeed (example, enter a climb to test climb rate at trim AS).