I thought an important distinction between the bunco situation and this one was that the husbands and children of the bunco members were only to make themselves scarce and not actually vacate the house. It was reiterated throughout that thread that the husband was perceived to be rude because he inserted himself into the group, not because he didn't vacate the house entirely.
That's a big distinction to me, "giving space" vs. "being gone".
So yes, if you want to be in the club you must accept (or vote to change) the group rules. If the wife does not want to literally vacate her house, tells her husband and is ignored then certainly that's a relationship issue. At the same time though, if the husband ignores her and hosts the group anyway, he's knowingly breaking their rules.
It's messy for the group if it comes to that sure, but I can't call someone rude for not wanting to leave their own home when they made that desire known to their spouse. It's a huge overreach of etiquette (in my opinion) to say this wife would be rude for not leaving her home when she made her needs clear. Her needs, even if ignored by her husband, trump guest comfort in this situation.
If my husband joined a group that mandated wives babysit children of the other members on their host night, I'd say "no way". I wouldn't do it. Full stop. If he goes ahead and joins the group, hosts an evening at our house, I am not rude for not babysitting the other member children.