Some ko rules only address a subset of repeating positions, and still allow for infinitely long games (sometimes ruling those as a no-result requiring the game to be played over).

The so-called superko rule simply states that no previous position can be repeated, which seems preferable.

excepting some crazy multi step ko that is possible in theory, it never happens in practice. There is nothing wrong with ko, it adds depth to the game. maybe they dont like ko becauase they have a weakness in their play and cant take advantage of them or defend against them. if you give your opponent a lot of ko threats they will end up winning most kos.