I would question your assumption that you are the dumbest person in the room. Your analysis points in quite the opposite direction. The rather toxic atmosphere you are describing, driven by egos with bitter attitudes indicates these people do not understand the meaning of the word team. And creating stressful atmosphere is usually counter productive to creative developments and innovation.

As a freelancer I worked in very many places. I have seen what you describe. I have also seen the opposite. Really smart people with educational attitudes helping juniors to fit in, learn and contribute to the team work.

My advice is focus on learning as you already do and find a more human/friendly environment to work in ASAP. Prolonging situation like this can take a serious toll on your life. And how long you want to work for/with assholes...?