The following content contains spoilers from My Hero Academia, Season 6, episode 22, currently streaming on Crunchyroll. Although the reason for Deku's sudden cold shoulder is understandable, the beloved prodigy has begun to encroach on jerk territory as of Season 6, episode 22, by mistreating those most loyal to him. There is a stark difference between creating distance to accommodate a safe zone and dishing out disrespect all over the show; however, it seems that for young Izuku, the end justifies the means, regardless of who gets hurt.
As the lines between Heroes and Villains become increasingly blurred, Deku appears to be flirting with the dark side in the name of justice. His heroic intent is borderline emotionally abusive and will likely be replaced by overwhelming guilt and regret once the smoke clears; following in the footsteps of Nana, Endeavor, Hawks, All Might, Lady Nagant, and so many others before.
Burning (More) Bridges
Besides maintaining communication, Deku simply ignores the Pro-Heroes who have sacrificed a great deal to ensure his safety and barely gives them the light of day. Endeavor will be mid-conversation, and Izuku will turn his back and walk away; Hawks dishes out specific instructions for dealing with Lady Nagant, which Deku promptly disregarded, while he shows little to no appreciation for All Might's efforts. It is possible to politely refuse a meal, as opposed to letting a thoughtfully made bento box go to waste while breaking poor Yagi's heart. Utterly disrespectful (particularly by traditional Japanese standards.)
One For All's Past Users are getting a taste of the same insolence after essentially being put in their place; Deku is the undeniable leader here, while the others' vast experience is apparently not worth the youngster's consideration anymore. As a relative newcomer to this whole Quirk experience, Izuku seems to think himself a master of the craft after receiving minimal training at UA High School, and mere moments with his full set of powers. Arrogance is not a good look for Izuku, and it will end up costing lives if this continues.
"Respect My Authoritah"
Distancing himself from his fellow classmates makes a great deal of sense, as Deku's friend group has a habit of getting involved in dangerous situations, and worrying about Class 1-A on top of everything else will be a distraction at the end of the day. However, a mere letter will not qualm the kids' fierce loyalty, as even those who aren't particularly close to Deku (such as Koji Koda, Toru Hagakure, and Hanta Sero) are willing to risk it all to protect him. Who is Isuku to decide who can and cannot fight?
Wielding One For All doesn't evoke a Godly status, and sitting around the school, worrying about Deku while waiting for the fight to be over is simply torturous for the likes of Bakugo, Ochaco, Shoto, and the rest. Dismissing their assistance during these tough times is indicative of Izuku's slight superiority complex; sure, he has a direct link to All For One, but that doesn't give him control over the Heroes or their plan of action. It seems that things will have to come to blows if Deku is to be knocked off his heroic pedestal.
Over the past several seasons of My Hero Academia, it would seem unfathomable for Izuku to challenge his friends to combat unless some kind of school activity or exam is underway; he has always been a peacemaker. However, Dark Deku has other plans in mind and is willing to fight his friends as a backhanded way of defending them, while his classmates refuse to back down quietly. It's safe to say that kid-glove treatment will be discarded in Season 6, episode 23, as heightened emotions take root in "Deku Vs Class A."
A Different, Dishonorable Deku
It's tough to compare, but it seems like All Might has drawn the short straw overall, as he is arguably seeing the darkest sides of Deku. Since discovering the true nature of One For All, the young Hero has been rather protective of his mentor, even more so since Yagi basically became powerless. However, in Season 6, episode 22, Deku captures an unnamed villain with Blackwhip and hastily jets off to the next fight, leaving All Might alone, in a puddle on the floor, with the dangerous escapee. To make matters worse, Izuku is fully aware that All For One might have a similar self-destruct set up for this hired gun, but doesn't wait around to ensure Yagi's safety until the authorities arrive. And little did he know, Hero Killer: Stain is there to witness the disgraceful interaction (and maybe take advantage or add Deku to his hitlist?)
Out of everyone involved, well, besides Izuku, All Might is technically in the most danger, as Sir Night Eye used his clairvoyant Quirk to predict his mentor's end at the hands of a villain. This death flag was given a one-year shelf life and, even though it was introduced way back in Season 4, the time frame still fits; All Might's impending doom is approaching, and yet Deku has clearly snapped and left the helpless hero to fend for himself during these troubling times.
From Hero to Zero
Even civilians are having a hard time trusting Deku; although all Heroes are currently in the dog box, Deku's new demeanor screams more Donnie Darko than Judy Hopps these days, which is starting to creep people out. And if the general public knew the truth of the matter, they would undoubtedly serve Deku (and One For All) on a silver platter to the Symbol of Evil, empowering him further and essentially embracing the tyrant as their leader. Many bystanders already assume that this rundown vigilante is in cahoots with All For One anyway and consider the possibility that he may even be a Nomu, particularly since the vigilante has frequently put his multiple Quirks on display.
Anger and resentment will be the civilians' greatest downfall, just like with Lady Nagant, Shigaraki, Overhaul, and many others, while Izuku is seemingly on his way to joining the list. Well, as long as All For One is conquered in the end, Deku's deplorable actions and questionable choices are all justifiable, right? Besides, if he loses his life in the process, it won't really matter at the end of the day. This pessimistic mentality appears to be fueling Deku's depression, who is now "rampaging because of impatience, wishing to be alone", and circling rock bottom while he's at it.