Shonen protagonists typically have a playful side, but in Chainsaw Man, Denji's eccentricities are more morally questionable than amusing. He receives frequent criticism for his crude behavior toward the women in his life and lack of sophistication.
Denji from Chainsaw Man is simple to write off as an out-of-control pervert, but that glosses over the socialization—or lack thereof—he had as a child.
Denji Lacks the Adulthood to Work in Public Safety
Before Denji met Makima and joined the Public Safety Unit, Pochita was his only true companion for most of his life. Being an orphan indebted to the yakuza, Denji didn’t have much in the way of a regular childhood. He turned to devil hunting in order to pay off his debtors and only really interacted with yakuza members -- who aren’t exactly paragons of morality -- throughout his childhood. With no parents, friends or proper role models, it's no wonder Denji wasn’t socialized properly and doesn’t have a concrete goal in life past getting a girlfriend and enjoying himself.
Even worse, despite his seeming worldliness, Denji is still rather ignorant due to his relative youth. Because of his incomplete understanding of concepts like love and romantic relationships and his enthusiasm to participate in them, he is vulnerable to people looking to exploit him. Himeno, a careless adult who ought to have known better, and Makima, who is preparing him for her own nefarious purposes, have already taken advantage of him.
When Denji reminds Himeno of his owed kiss at their department dinner, she claims to be too shy to do it sober. All throughout the dinner, Denji’s immaturity is highlighted in stark contrast to the older devil hunters. He even looks much smaller in stature than the rest of the group, but apparently that wasn’t enough to deter the drunken Himeno. Denji eventually gets his kiss -- and a mouthful of vomit for good measure -- but that’s not all. Later that night, Denji is very nearly assaulted further, and receives nothing for his trouble past a half-hearted apology and a sketchy alliance to help him woo Makima. Ignorant as he is, Denji is ecstatic.
How Denji was abused by Makima and Himeno
Heartbroken after such a disastrous first kiss, Denji unsurprisingly turns to Makima for comfort. Although he does receive some solace in her inviting arms, the moment is immediately perverted when she presents a proposition much like the one that earned Denji a kiss from Himeno; if he kills the Gun Devil, he gets to live out his wildest fantasies with Makima. It seems like a “fair” proposal at first, with both parties gaining something of benefit in the end, but Makima’s original arrangement with Denji prohibits him from ever refusing one of her requests. Once she made the offer, he had to accept it no matter his own feelings on the matter.
Not to mention the absurd scale of the assignment Makima has given Denji right now. Gun Devil has been hyped by Chainsaw Man as having destructive power well beyond that of any other devil and exceeding that of whatever Denji has accomplished. Setting a young devil hunter against it is similar to giving him a death desire, and Makima is well aware of this.
Denji believes he has a special relationship with Makima, which explains his eagerness to comply with her requests, but the callous manner with which she regards him in his absence suggests anything but. He’s being manipulated and exploited by someone who is only interested in his powers and potential as the Chainsaw Man and the worst part is, Denji doesn’t even seem to realize this.