How CDC lowers the number of myocarditis cases by using a restrictive case definition, even though CDC had a perfectly good case definition when smallpox vaccine caused myocarditis in 2003

https://www.cdc.gov/vaccines/acip/meetings/downloads/slides-2021-06/03-COVID-Shimabukuro-508.pdf

Go to slide 23 for the current 2021 CDC myo/pericarditis case definition

Below is a better, more inclusive case definition used by CDC in 2003.  What is CDC's justification for changing it?

https://www.cdc.gov/mmwr/preview/mmwrhtml/mm5221a2.htm#box