I think the LW is mad that their daughter is married to a woman. They may not realize it, and if the daughter were married to a man and the place were in exactly the condition it is now they might or might not find some other way to complain about it but likely wouldn't complain about him. (And it probably goes without saying that if their son were married to a woman and the place were in exactly the condition it is now it would definitely be the son's wife's fault.) But I think there is unexamined homophobia in there for sure.