Because they do whatever they want. Some people are jealous, some people just hate them. Same reasons people tend to hate the pirate emperors without meeting them.

Because the idiots up the chain of command are arrogant jackasses who think they can control them with money, and they don't listen to common sense.

And like it or not, they're desperate. Not enough marines, too many pirates, and Dragon's Revolution is starting to corner them into a wall.