People invite poeple to a group mainly for 2 reasons.
1st they like them.
2nd they can improve the group because they are so active, help them win, they are popular and more members will follow or they are a new group that desperately needs new members.
The first one is more often the case.
The thing is that this evolved from players not resigning to taking a vacation when it was 2-3 moves to mate. Also if it was a 7+ move a day game the player would take almost all the time to move. So 2 moves times 7 is 14 days for a game to end. Then they take a vacation for a couple days then move and just 1 move before mate they take all of their 30 days vacation.
This is the person that makes one to think i can not stand them.