Same logic terror used to login 30 mains vs sup, when 3 or 4 of our accs were 30 def instead of 25. Certain clans realize they will never get the competitive edge without the mains, especially starting out or after a slump, it makes sense to boost some moral with your members.
And anyone who thinks "every clan brings mains" isn't really on for weekends. A lot of clans have mains ready in case they need to retaliate against z/rage capes. The issue stems from the ones wearing Z or Rage capes, taking sides, having demands that will never be met. They're killing their own community, new clanners don't join clans anymore and stay because of this. These 2 capes kill the clan scene, I don't care who is in them.