I am also in favour of E2E by default for everything without any device or cloud based scanning. However, Apple doesn't want to be caught in having developed a service that enables for child exploitation. Doing nothing may have even more invasive requirements legally forced by government, so Apple is stuck with a dilemma. Also lets not forget that Apple should also not want child exploitation to occur and therefore also should do something.
The question I have for drenvuk is how else is Apple able to prevent or detect child exploitation and the storage or distribution of content such as this on Apple's services?