Forum:Stardust and Exiled Force with effects negated

Hello, i am VERY confused by something i read: here's the link about Exiled Force with its effect negated by Forbidden Chalice http://yugioh.wikia.com/wiki/Card_Rulings:Forbidden_Chalice. It says that since EF 's effect activates on field, even though it has been tributed as a cost and resolves in the grave, is negated by Forbidden chalice cause the effect activates on the field.

However, at this link http://yugioh.wikia.com/wiki/Forum:Stardust_vs_Skill_Drain it says that if Skill Drain is face-up and stardust activates his effect, it is tributed as a cost and resolves in the grave, but is not negated by Skill Drain cause it only negates effects on the field.