It's right.

When did you start using computers? I'm getting older now, and some people weren't alive when I first used a computer.

It's because the older programming approach was to just tell the computer how to do the thing - and the modern approach is to write a framework inside which you write a framework inside which you write an inefficient version of the thing because it's constrained to the tools available in the framework stack.

Old-school implementation of "scroll up": copy pixels then redraw the pixels at the bottom.

New-school implementation of "scroll up": delete virtualized rows from the beginning of a DOM table and add more to the end. Change the height properties on different parts of the scrollbar. Relayout the whole DOM, several times if you're not careful. Redraw the whole screen.