Basically, all dates are electronically stored as the number of seconds since the epoch (1/1/70). Unsigned integers can only be positive, so if you try and calculate a negative integer (without catching it in your code), it wraps round to the maximum value, which for a 64-bit integer is large, to put it mildly.
The video doesn’t explain (or know) why this happened but assuming some calculation involving the current system time, they end up with the year 292277026596 (according to the video). The video also doesn’t explain/know why this crashes the system but apparently it does.
