So is it like Valve games 12 years ago when one players high ping affected the whole game? lol If you're connecting to dedicated servers in the right region and you ping well why should other players ping be detrimental to your experience (not counting extreme cases)? I don't understand why it's handled this way
Well, yes and no. It doesn't drag down the entire session with lag but the entire thing works just like ( or it IS ) client side hit detection. Instead of server deciding which bullet kills, it's the clients that does it.
So you're on a shit connection, you see a guy and shoot straight at him - You basically tell the server "I killed him", the servers says "Alright" and no matter where the hell he is, he'll die. On his screen, he can be behind a wall and warp back 5ft and die because that's where the server registered you as dead. So it compensates you for having a shit connection.
However on the other end, people with the best connections aren't getting proper up-2-date information on the players position and they are usually milliseconds behind, meaning when you see a guy JUST coming around the corner he has already seen you and is firing, which ends in those fucked up death moments.
Client side hit detection is the work of Satan and is used for 2 reasons: caters for people with shit connections and puts less strain on the server(s). However it's becoming the industry standard in most games. Also the reason why even PC games with fancy dedicated connections and whatnot suffer from this crap.