Re: Did someone not do their EMC/FCC/CE testing then?
> "can even cause the connected Macs to freeze, requiring a restart." (? what's freezing here: the screen, the Mac, both?)
At a guess, it could be something like: the monitor goes faulty and repeatedly attaches and detaches from the display output on the Mac's video card; the Mac has to change the window manager & video card state when a monitor is attached or detached; the rapid toggling tickles a bug in the video driver or window manager, leading it to freeze; and you don't normally experience that bug because it's not normal to be able to repeatedly plug and unplug a monitor that quickly without a hardware fault.
Or maybe when the monitor's bugged it does something amusing like sending totally bogus EDID information that tickles a bug somewhere. "I have a width of -3200 pixels and I want to be driven at 4MHz" or something equally silly.
Given the complete uselessness of faulty hardware, bugs which only occur when you have faulty hardware plugged in aren't top of the priority list to fix. It's pretty reasonable that a problem like that could be left lying around for years.