On two separate occasions I sent in a ticket to Riot Support to report players that both said "KYS" and some other phrases in the chat. My understanding is that "KYS" is a severe enough phrase to warrant an immediate 14 day ban. On one of the reports the offending player received a 14 day ban (which I know because I checked their account to see their match history) and the other player has not received anything more restrictive than a chat ban since the account is still playing. The screenshot is what I managed to grab in the pre game lobby before somebody dodged.
TLDR: How does this behavior NOT warrant at least a 14 day ban?
P.S. please disregard the frame, I am very new and don't have any color palettes.