Any run of three characters in sequence, forward or reverse, is marked as invalid. 123 876 432 would all mark the whole password as invalid, even if they only take up half the string. Yours would pass though, yes.
His is two vertical runs along the keypad. The forbidden ones are horizontal runs. That's why it's stupid. Any modeling of passwords humans would generate for use on a keypad should forbid 741 by the same logic that forbids 123.
