How I understand it....
League is a server-side based game, meaning the 'host' is actually a Riot originating server and not a player's computer that the various players are connected to. This differs from peer-to-peer hosting multiplayer games like Call of Duty. CoD uses a matchmaking system to find the best host player and runs the game logic through the chosen player's system.
In other words, CoD's ping and connectivity is based on how good your connection to hosting player is, whereas League's ping and connectivity is based on how good your connection is with a server within Riot facilities (located largely in the west coast). This is why some people can be disconnected during a disruption and others stay, their network path runs through different hubs to get to said server, and this is also why a lot of Riot's major connectivity problems (i.e. March's DDoS shenanigans) are with the ISP's in between and not the servers themselves, sorta like how a delivery truck will be late if the roads are bad but it isn't the delivery service's fault.
I'm not a professional though, I could be wrong.