You have valid points, Yuki, but you are forgetting one thing (although the series itself is forgetting it as well often enough). It's the future. Even today the most modern fighter jets would be useless in the air if their computer controls broke down. Now, something like a giant man shaped robot flying in the air wouldn't stay there for a second (or to be precise it would stay there for as long as it would take to drop down) without a highly sophisticated AI controlling system. We can thus assume the pilot has it actually pretty easy up there, probably much easier than the fighter or helicopter pilots of our days. And thus when they get a superior mobile suit, it will either fly steadily by an unexperienced pilot or perform crazy stunts by somebody like Graham, Ali or Soma. However, it won't crash down even if the pilot is somewhat unaccustomed to it because in the end it's the AI that's keeping it in the air at all in the first place.

What comes to the HRL decision, once again, the Throne was decimating one of their bases, killing people and destroying property and equipment. It might have been wise to be careful with their brand new equipment but you don't need to be a klingon to say avoiding the fight because of that would have been an epitome of cowardice and it would have sent many more people to their deaths if the Throne had been left unchecked in their murderous ways.