“I know what a skeleton looks like.”
“There were letters. I can read.”
These two lines alone should tell the viewers exactly the way the COI wanted Simon to feel. They wanted him to believe he was nothing but a murderer, and was good at nothing but that. He has probably spent however long in jail being told he was an “uncivilized drooling brute” by these people and has constantly had to prove them wrong.
Grace is book smart. He’s got all the big math equations he can just do in his head and the doctorate level knowledge on exactly how molecular life works. Yes, he is smart, but in the movie he is constantly shown to be a little dumb about it. Grace gets frustrated when things go a little wrong. Xenon turned into a solid and he didn’t like that and threw the scanner at the table. Astrophage turned out to be water based life and he threw a hissy fit about it. He gets mad about things quite a lot actually, but most people just point out how “clumsy and pathetic” he is and make that his whole character trait.
Simon gets mad because he’s in a literal life or death situation where the people in control of that decision can’t decide which answer they like. “Just go down and find something and you’re free. Oh you found something? We’re sending you back down for proof. Btw we still blame you for the radiation thing even though we didn’t tell you about it, have fun with the concussion. Wait, you’re still alive down there after several days? Sorry, you’re staying down there and going back for that black box, but then you’ll be free. Well, nevermind, you’re dying down there.” All of that while he is in an impossible situation. He’s having to navigate a blood ocean in a vessel that’s falling apart with an x-ray camera in like, the most rudimentary form of echolocation ever. And he doing an incredibly good job at it. He literally is able to map out an entire section of the blood ocean that was completely undiscovered by literally converting time traveled into distance traveled into squares traveled on the map. HIS IS ACTIVELY CALCULATING AND DOING MATH IN HIS HEAD DURING THESE MAPPING SCENES.
As someone who did grow up in an actively known cult, I feel I know at least a little of what his situation is like. When I started the process of leaving and deprograming, I felt stupid. I felt like I knew nothing about the world, even though it was the exact same world I had been living in all my life. People also either pity me or just think I’m plain weird because “how do you not know this basic thing?” There was literally a saying of “in the world but not of the world”. They wanted us to be isolated from anyone who wasn’t the cult. They make you purposely ignorant on things so you don’t question things.
In Simon’s case, the COI actively used that against him. “Oh you don’t know this pretty basic thing? Wow you must be so dumb and stupid, nothing but a killer. Can’t do anything but hurt others, you’re so evil and filthy.”
Simon is what we’d consider street smart. He thinks in his feet and improves and he’s really fucking good at it. Need the camera light but can’t stand at the button? Tape it! It’s not his fault the tape doesn’t work. Need to keep moving forward but you also need to map that shit down? Use the binder to keep the lever forward. Hey I don’t have any more water but this light is water activated? Spit in it. There is literally a scene where he is counting the seconds it takes to move a specific distance, he is actively finding new ways to navigate an entire submarine near completely blind.
He is also constantly apologizing about things. Even to inanimate objects. He doesn’t like when he gets mad. He simply also has every reason in the world to be mad in his predicament.
Grace is smart, yes, but Simon is also smart. He and Grace are actually incredibly similar in their anger. Simon is simply called a threat for doing so because his circumstances are different. Either people need to stop showing Simon as the mindless attack dog his isn’t, or they need to start showing Grace as the ticking tomb bomb he is. He loves to bottle things up and pretend they don’t exist and then explode about it later. Stop making this seem like it’s just Simon and it’s “just his nature”. Anyone with a sense of media literacy can tell you it’s not.