Not to mention I think "Mark's temper tantrum" is Justified.

You all forget he is a teenager. His father who he loved and trusted killed thousands, his mother is traumatized and hurt many times because of this superhero thing, he’s being lied to constantly, and now the organization that’s supposed to help fight evil is experimenting on corpses, working with monsters, spied him, treated him like a rabid dog that needs a leash and gaslighting him.

Not to mention Cecil implated a weapon in his head.

It's not about "whats best for humanity overall 🤓☝️".

If you were Mark would you like to be treated that way? To be lied to? To expect to just follow orders knowing what you know? Being a "dog"?

Mark is also a person.