That only applies to TV sets, computer monitors operated at much higher frequencies outside the human hearing range.

They weren't that high frequency. I could hear computer monitors into my twenties at least. I'd guess somewhere around 20 - 22 kHz. CRTs were largely replaced by LCDs by my late 20s/early 30s, so I don't have a good sense of when I stopped being able to hear frequencies that high.

VGA monitors had a minimum horizontal frequency of 31 kHz (480p at 60Hz), way outside the human hearing range.

And arcade monitors, or at least the ones I've been around do. I can hear an arcade machine in a different room

Most arcade monitors operate at the usual 15 kHz, although some later games operated at 24 kHz (medium resolution) and 31 kHz (high resolution).