It is difficult to litigate what reason is enough of a reason to kick someone from an instance. We try to make sure most kicks are valid by requiring a majority of the players in an instance to vote yes to the kick and by limiting how many kicks you can do. People are saying that yes, they want to kick this person, even knowing that they won't be able to kick the next person for quite a while if they are worse. It isn't perfect, of course, but it isn't expected to be. Always open to suggestions.