Because they want to force us to change to their immorals
Think of "Gay marriage" -- the Episcopalians allow this, but there are gay Catholics who want the CAtholic church to allow this -- why? Why do they want to stay Catholic if the Church "oppresses them"? Who not join the ECUSA?
No, they want everyone to be forced to 'accept them' -- that's the way with liberals
Liberal elites won't have to fight for gay marriage or brother/sister marriage or man and chimp marriage. They can have it all - without us objecting - because we'll be living somewhere else. They'll be FREE - free at last as they like to say...
You might be right - that their real goal is to bring us to our knees - to humiliate us. But they don't have the courage to speak that truth so they won't. They'll 'get their religion' and my guess is they won't bother attending. It's all a stunt for them - if you're right - and you might be... If so, they'll totally lose interest when they've 'won'.
When we're gone, how will they entertain themselves? Luckily we don't really have to know or care... This is a goal worth working toward.