As a UX designer, the first part is part of the reason. Companies actually “want” you to continue to scroll and to click the view more button. Every time you view more, they get more ad revenue and more data.
Endless scrolling is an accessibility and data conservation nightmare. It’s also arguably grey UX, as it encourages scrolling addiction. Having the user have to make a decision to load more saves the user data, and keeps the page from shifting context without user input. Global apps should consider the needs of the bulk of the world, which is still on pay-for-data plans.
The answer tends to be to also implement server-side sort and filtering that includes “show new.”