According to this video, cats’ frame rate is 50 hz, a bit slower than humans’ 60 hz, but with much sharper vision. So perhaps it’s the pixel size and not the frame rate that matters most. Dogs do have a higher frame rate, so your hypothesis could fit their behavior if dogs don’t watch TV.

https://youtu.be/Gvg242U2YfQ?si=Tsfan1-W2DdrDkVi