
I have not seen anyone demanding anything. I'm not understanding the attitutes almost villifying this couple because they don't drink - as if they're doing something wrong.
Neither couple is doing anything wrong, they just have different beliefs about alcohol.
While I obviously feel differently than most here, to me, not serving alcohol at a party where a guest you are trying to welcome likes to drink is not the same as serving alcohol at a party where you are trying to welcome a guest who doesn't approve of drinking. I assume the absence of alcohol wouldn't be a big deal, while the presence of alcohol might be upsetting.
As I said before, the host is well within their rights to serve whatever they want. If protecting those rights is what is most important in this situation then that is what she should do.