The term is "theoretical computer science." Not just "computer science"
https://www.wikiwand.com/en/articles/Computer_science
https://www.wikiwand.com/en/articles/Theoretical_computer_sc...
The OP is making a claim on "theoretical computer science" NOT "computer science". Hence the title "What is theoretical computer science".
If you look at the wiki entry you will see that "Theoretical computer science" is highly mathematical and different from "computer science".
Honestly even I mis-used the term and this leads to tons of confusion. The naming of everything really changes the way people think and mixes everyone up. It's entirely a linguistic problem.