I assume that whoever chose the text for the tags isn't really familiar with all game types, as eliminating a team-mate is sometimes a valid, potentially game-winning strategy. Mostly in games with spoils.
I always assumed the tag was meant for people who did it when it wasn't necessary, whether because they didn't know what they were doing, weren't a good team player, etc. Just my $0.02
High score: 2200 - July 20, 2015 Game 13890915 - in which I helped clinch the NC4 title for LHDD