... what does it even mean to be "the opposite of science"?
Science is the process of going from data to conclusions. The opposite would be to start with the conclusion and try to find data to confirm it. That's exactly what creationism and its bastard child ID do, the opposite of science.
What does it mean to be the opposite of chemistry, or biology, or physics?
That's an entirely different question. Demolition is the opposite of construction but there's no opposite to a hammer.
All that you are decribing here is "data analysis". Science involves data analysis, of course, but so do many endeavors outside the world of science. Science is much more than just data analysis!
Science analyzes data in one direction and ID analyzes data in the opposite direction - which is why ID can be said to be the opposite of science. There's no need for you to nitpick about such an obvious distinction.