The protagonist of Demon Slayer, Tanjiro Kamado, is known for his kind heart and sometimes over-generous nature. Tanjiro treats pretty much everyone he encounters with the utmost respect even if they don't return the favor. From aggressive bullies to man-eating demons, Tanjiro rarely ever acts in a hateful manner. Some fans of Demon Slayer view Tanjiro's compassionate personality as a hindrance to his character. Why would Tanjiro be so forgiving to monsters that have slaughtered innocents and have tried to murder him and his allies? This seems like a flaw initially, but Tanjiro's kindness is in fact his greatest strength.
Compassion Doesn't Get in the Way of Being a Demon Slayer
So far in the anime, after his training under Sakonji, Tanjiro has never hesitated to kill an evil demon. Once Tanjiro knows that a demon has taken an innocent life, he always acts with the full intention of killing them. Tanjiro understands the threat that evil demons pose to human life and is willing to do whatever it takes to protect the innocent. Just because he doesn't hate every enemy he encounters doesn't mean he's not willing to make sure that demons pay for the wrongs they've committed. Tanjiro is a proud member of the Demon Slayer Corp and accepts the responsibilities that come with the position.
Compassion Allows Tanjiro to See the Good in People and Demons
Tanjiro knows better than most people that most demons did not choose to become man-eating monsters. Many of the demons that he meets were forced to become monsters by Muzan, the same man that killed his own family and turned his sister into a demon. If Tanjiro acted with hate and slaughtered every demon he came across he would never have realized that good demon can exist, like Nezuko, Tamayo, or Yushiro. These are powerful allies that have saved his life multiple times. By having compassion and sympathy Tanjiro maintains hope that his sister is not beyond saving.
Tanjiro's Compassion Aids His Pursuit Goals as a Demon Slayer
Two main goals motivate Tanjiro on his journey. The first is restoring his sister and the other is protecting humans from demons. In both cases, Tanjiro is fighting to preserve humanity. He knows that at one point in time every demon was a human, which means that they had someone that cared about them the same way that he cares about Nezuko. He understands that before they were demons they probably lived full lives. They lived, loved, and suffered just like any other human. Because they used to be human, no demon can be completely evil. By killing evil demons and preventing them from taking more lives, Tanjiro is honoring their past, human selves and allowing them to atone for the sins they have committed. Tanjiro makes his opinion on demons clear when Giyu sees Tanjiro show sympathy to a demon that was killed.
"In order to soothe the spirits of those it killed," Tanjiro says, "and to make sure it claims no further victims... I will swing my blade down and lop of the head of any demon without mercy! But I will not belittle those who regret their actions... and suffer over the things they did as demons. Because demons were once human. Because they were like me."
All Tanjiro wants to do is prevent more suffering from taking place. He wants to stop the same kind of suffering that happened to him and Nezuko from happening to anyone else. Killing evil demons prevents that suffering from happening but he doesn't need hate or vengeance to make that happen. By staying compassionate and sympathetic to those around him, including his enemies, Tanjiro keeps his true goal in focus: protect the humanity that exists in humans and in demons.