This has nothing to do with jump potions. Bad players will be bad whatever the level. Jumping just makes them have access to content you want to be safe in, but otherwise they would still plague the levelling roulettes and such, making the problem just as bad. It has to do with entitled little whiners who refuse to do a tiny bit of research before entering a dungeon or a raid to make sure they carry their own weight. It's the mentalities, not the system.