I believe the idea is that if you cut 2,000 players (low population hours) 4 ways than a difference of one team having 100 more than the other can be massive.
Team 1 - 600
Team 2 - 500
Team 3 - 450
Team 4 - 450
During high population, our player count is more around 14k, so 100 peoples in not team defining.
Team 1 - 4100
Team 2 - 3600
Team 3 - 3450
Team 4 - 3250
While there may still be a Team with notably more players than the other, it's more lost in the overall numbers as opposed to one or two clans that decide to wake up at 4am to grind out wins for their team. You might think, "Why would someone care about their team winning a bunch at 4am?" The answer is, because there are some extremely competitive folks that will go to massive lengths to win at anything.