Generally it's not just a weak defence ritual but one which actively attempts to lose, rituals which do 90+% damage to themselves even if the opponent doesn't do anything.
Also if someone's attacking and getting a win they're going to want lots of VE so they get lots of XP. It's a waste of a win for them if they get only a tiny amount of VE cause then they have to go and get a loss to compensate for that win.
The most effective loss gathering rituals are those which damage themselves, have a lot of VE and regenerate that VE either from the creatures own regen stat or the players. That way it's hard for people to attack you and lose, they're rewarded with lots of XP beating you, and you can reuse the same creatures in a copy of the same ritual again and again.