Quote 1
[The manager]: "'He [Kurtz] is very low, very low,' he said. He considered it necessary to sigh, but neglected to be consistently sorrowful. 'We have done all we could for him - haven't we? But there is no disguising the fact, Mr. Kurtz has done more harm than good to the Company. He did not see the time was not ripe for vigorous action. Cautiously, cautiously - that's my principle. We must be cautious yet. The district is closed to us for a time. Deplorable! Upon the whole, the trade will suffer. I don't deny there is a remarkable quantity of ivory – mostly fossil. We must save it, at all events – but look how precarious the position is – and why? Because the method is unsound.'" (3.19)
The manager’s words mean nothing. They cannot even get near the heart of the situation because his thoughts are so warped by his own greed and jealousy.
Quote 2
[The manager]: "'He [Kurtz] is very low, very low,' he said. He considered it necessary to sigh, but neglected to be consistently sorrowful. 'We have done all we could for him - haven't we? But there is no disguising the fact, Mr. Kurtz has done more harm than good to the Company. He did not see the time was not ripe for vigorous action. Cautiously, cautiously - that's my principle. We must be cautious yet. The district is closed to us for a time. Deplorable! Upon the whole, the trade will suffer. I don't deny there is a remarkable quantity of ivory — mostly fossil. We must save it, at all events - but look how precarious the position is - and why? Because the method is unsound.'" (3.19)
Let's count the ways in which the manager is depraved: first, he misrepresents Kurtz's condition and twists his words. Second, he tries to attack Kurtz's "method" by calling it "unsound." Finally, his words are just empty—which doesn't sound so bad to us, but is evidently the tipping point for Marlow. This guy is definitely getting unfriended.
Quote 3
"'Yes,' answered the manager; 'he sent his assistant down the river with a note to me in these terms: "Clear this poor devil out of the country, and don't bother sending more of that sort. I had rather be alone than have the kind of men you can dispose of with me." (2.1)
Kurtz is so powerful in the company that he can kick out his assistant and order the Company not to send him any more "of that sort." Must be nice—until it makes you crazy.