Obviously, the emergency lane is for emergency vehicles. People who use it to skip traffic in a jam are fucking assholes. However, vigilante Karens blocking the lane so that the assholes can't use it to pass make that entire lane useless for even longer. Neither behavior is acceptable, but at least one isn't worsening an already stupid scenario.

Nobody likes line cutters, but contributing to the danger by blocking the lane is worse than cutting into it. Sanctimonious, selfish behaviors like that can actually get people killed. Nobody blocking the "line cutters" can know whether the vehicle using emergency lane isn't actually in some kind of emergency. In America, stunts like that have a real possibility of getting yourself shot.