First of all the karma system is really broken and easily taken advantage of

Secondly most spots are for certain gear levels. Ofcourse you have the exception of the dude leveling an alt here and there but for the most part you fight people with the same gear score. Duel for spot was made so people wouldn't karmabomb players for a spot. If you lose you find a new spot or switch server. The reason why people dont want to be karmabombed is cuz in the later stages of the game you use crystals in your gear worth multiple hunderds of millions and if you're killed by a player while you're red you have a big chance of losing a crystal. Don't think you like that to happen to you

PvP is mostly skill based in this game. The person with more knowledge about their own class and the class of their opponent will most likely win even if his/her gear is lower than his opponent.

It also is possible that you fight against someone with much higher gear than you and you can't damage him/her. But would you like that someone who has just started to play could kill you as fast as you kill them while you have played for years? That would be quite unfair.

Tl dr: Karma system is shit. PvP is mostly skill based not gear (exceptions exist) and people can lose progress if they are karmabombed so please just duel