Your video shows what happens when an LCD panel is unable to synchronize to the incoming signal. The color data for a particular pixel on screen comes through the cable at a specific time. If the "SyncNovice" is too early or too late sampling that data, it will appear displaced one pixel to the left or right from where it should be. The timing error relative to each pixel continually changes, which is why the image visually swims like that.
On a lower resolution, the sample frequency (called the dot clock) is lower, meaning the color data are further apart in time. Therefore, the same timing error as before can still recover the correct pixels since it falls within a wider window of time.
LCD monitors from almost 20 years ago typically do not perform as when they were new because of choices made in their construction. One problem in particular was some of the capacitors commonly used, which because they were very small, tend to dry out more quickly than larger types. As they dry out, they lose the ability to stabilize the voltages inside the monitor, which introduces more noise and reduces the timing accuracy of the color sampling.