Probably for talking shit or spamming ?
As a wise Star once said, the vast majority of people who get kicked or muted have some idea why it happened, but still come and ask rhetorical questions.
You can complain on Venice's associated IRC channel (if it's one of the /dev Venices you are talking about).
Masters on this game are playing this game for years. They know if the "two" teamkills are on purpose or by accident. They know if players try to take advantage of that 5 kill limit. Oh btw i remember this: