Servers are weird. Most of the time lag is caused by the game hogging the hosts system, most people will blame it on the person with the highest ping, it's true that every player will take away some of your upload speed, so if you have a bad upload speed then when you get to a certain amount of players all pings will shoot up, the only people who will cause a server to lag with their ping is people on modems but I disagree with ping kicking anyway.