Why do lawyers defend criminals, knowing that they are guilty?

Let me give you an example here. If a person is accused of intentional homicide by the inspection agency, but he is actually innocent, he didn't kill anyone, and all kinds of signs from outside are very unfavorable to him. On the surface, it seems that he did kill someone, but most people think that he killed someone and deserved it. At this time, if the defendant does not have a lawyer, or does not have a good lawyer, standing in the defendant's position and defending him wholeheartedly, it will lead to misjudged cases. And if this happens in the vast majority of cases in a country, can you say that the justice in this country is fair, regardless of whether the defendant really committed the alleged crime or is innocent? Can the rights and interests of citizens in this country be effectively protected? Indeed, lawyers defend bad people. Such behavior is unacceptable to most people, which makes most people sneer and think that such lawyers are not good lawyers. They are insatiable and heartless. This is also the case. Lawyers who defend bad guys are not bad guys. They defended a bad man regardless of the criticism of the world and the great pressure of public opinion, just to stick to their beliefs. They believe in the spirit of freedom and everyone's rights should be properly and fully protected. At the same time, they achieved judicial justice and made great contributions to the judicial progress in China. I really appreciate the dauntless spirit of lawyers who defend gangs in Chongqing. It is really not a good thing for lawyers to defend such an unscrupulous gang. Judging from this case alone, these bad guys deserve to die, while good lawyers advocate bad style to let the bad guys get away with it, which can be put in the context of the whole judicial system in China. This has indeed made outstanding contributions to judicial justice, and it also reflects that China has taken another step in safeguarding human rights.