I do remove animated GIFs that distract my focus when reading text.
I haven't yet felt the need to block CSS animations. Up to now, UX animations aren't so distracting they impede my reading. I think this may be because CSS is generally not used in ways that constantly distract while reading text.
A CSS fade or transition on scroll doesn't bother me as much as animated video/GIFs.
It can bad enough that I'll find the auto-playing video element in my browser's DOM inspector and delete it.