Why was Russel Mulcahy fired as the director?

This is what Sylvester Stallone had to say about the matter:

https://en.wikipedia.org/wiki/Rambo_III#Production

The canvas of this movie is so large you have to constantly think 10 scenes ahead. You can't wing it. They didn't go into the Battle of Waterloo not knowing what their strategy would be. Well, this movie is kind of like a cinematic warfare. We have a huge cast and crew (more than 250 people) and tough locations to deal with. Everyone and everything has to coordinate.

http://legacy.aintitcool.com/node/35350

Yes, Russell Mulcahy, I thought did a brilliant job on several music videos and eventually “Highlander”. I remember calling him from an editing room and telling him what a wonderful job he had done. He answered back in a bored fashion “Why thank you darling.” So I hired him. He went to Israel two weeks before me with the task of casting two dozen vicious looking Russian troops. These men were suppose to make your blood run cold. When I arrived on the set, what I saw was two dozen blond, blue-eyed pretty boys that resembled rejects from a surfing contest. Needless to say Rambo is not afraid of a little competition but being attacked by third rate male models could be an enemy that could overwhelm him. I explained my disappointment to Russell and he totally disagreed, so I asked him and his chiffon army to move on.