WARNING: The following contains major spoilers for Spider-Man: No Way Home, now playing in theaters.
In Spider-Man: No Way Home, it's easy to point fingers at the debacle that occurred, which tore a rift open in the Marvel Cinematic Universe and allowed the original Sony Spider-Verse to spill in. Peter Parker could be blamed for asking to mind-wipe his reality, while Wong can be held accountable too for leaving the spell to be carried out. However, factoring what came before in the MCU, it's clear that both of these guys aren't the worst Avenger -- it's Doctor Strange.
Now, this doesn't absolve both, but Strange needs to shoulder most of the blame, as he hasn't learned from past mistakes. Wong warned him again tampering with space and time in the opening act, yet he did. At any point, he could have told Peter no, especially when the teen started changing the parameters mid-enchantment, but Strange soldiers on even after sensing danger.
It's unbelievable how he entertained it as if it were an experiment, ignoring how the fabric of reality could be in damaged. What's also disconcerting is Strange endured this drama with the Time Stone against Kaecilius, and it's why Baron Mordo left the order of Kamar-Taj; he couldn't stand Strange playing god. Coupling that with how Strange saw Thanos mucking up reality with the Infinity Gauntlet, he ought to have known better and been an adult.
The sad thing is, he then asks the teens to "Scooby-Doo this shit" and help him fix the mess, when he should have fessed up and called in Wong, other mages or Earth's Mightiest Heroes because this was an extinction-level event. It's disappointing to see Strange so nonchalant about it, which now has him looking incompetent.
He's just not fit for the station he holds, with his lack of foresight also leading to Green Goblin killing Aunt May as the chaos unfolded. Strange proved once again, he's no better than the teens he tasked with this larger than life task, except he is supposed to be the adult in the situation.
It's reinforced by him having full moon parties and brainwashing Wong too, which was a red flag from the onset. Ultimately, even mind-wiping realities was something he should have also discussed with his mystical council and the Avengers, as it messed with their memories and tinkered with the roster by removing Spidey, thus confirming Mordo was right. Strange hasn't grasped that with great power comes great responsibility, and sadly, he'll need Wanda to patch things up as the sequel to Doctor Strange shows there will be deadly consequences to come for his poor choices.
To see Doctor Strange dishonor the Avengers' mantle, Spider-Man: No Way Home is now playing in theaters.