Well, my players just shrug and have a good laugh when their little expeditions into ancient ruins produce another hundred casualties among the armsmen that escort them planetside.
When I read some of the replies, I have to say that the game has already slipped all reigns there. Even the most militant RT is out there for adventure and business. In a very dark unknown, where you need at least half-way trusted crew! And pardon me, an RT with ultra-puritan or monodominant crew has earned a cruesome death. Even among the Sororitas or SMs you find some less triggerhappy examples, which are the ones travelling with the RTs.
A group which does not care for any losses has to feel the hammer of the GM sooner than later. Psychpaths among the RTs have a well-earned reputation of being "removed" for the well-being of all out there in the endless Dark.
I do not argue from a "modern" standpoint. You have to be eccentric to become part of RT expeditions. But what some players/GMs post here, is neither eccentricity nor (needed) expediency. It is simple bloodlust and a vacuum in the head of the chars, hell sometimes the Orks have a better reason!
The successful RTs have to make some hard decisions and take acceptable losses as well, but sound reasoning adds to their legend. Butchering your way along the stars might be successful in the short term, but sooner than later others will take action against such loose cannons.
Have you read about Chorda's special ability, for instance? 'Acceptable Losses' ? Or her M.O. in general?
Most of the successful Rogue Traders in the expanse are ruthless madmen, separated from pirate kings and marauding warlords only by a Warrant of Trade. They use and in some cases abuse people, placating only the key personnel they need to keep control.
A missionary barbequeing hostages with the kidnappers is more than fitting - even RL governments have that "do not negotiate" rule; its not farfetched to assume that the Imperium or a Rogue Trader is not even going to make the attempt of a farce, unless the hostages are important. Same goes for most examples listed here, especially the ones involving Xenos.