Because MIT is one of the most competitive schools in the country. Not only is your subject test low, your ACT math is also low for schools of that caliber and you chose not to take the most rigorous science courses in HS. Nothing you’ve shared shows you are a good academic match for MIT. Being URM is not going to overcome low scores at a school that is STEM focused.
I don’t mean this to sound harsh but to be a wake up call. As others noted hopefully you have real match and safeties you’ve applied to.