I work with adults with learning disabilities in a supported living setting. Most of them are capable of consenting to sex and without a deprivation of liberties order in place there is little staff or anyone else can do to prevent them having sex and DOLs are not easy to get.
Of course, they are also extremely vulnerable to abuse and in those scenarios we do have an obligation to step-in, although, even then our power to help is limited to reporting to SS - who would then investigate and if appropriate apply for a DOLs. We cannot force an adult to ask a guest to leave their home. We can strongly advise against it but we cannot force them nor should we be able to. They are adults.
Are any of these adults capable of raising a child? Possibly, a few of them with the right support but generally, no.
Having seen first hand what evidence is required just to take control of someone's bank account or grocery shopping against their wishes I have every confidence that this situation was not taken lightly and a serious and comprehensive review of the woman's needs, abilities and living situation would have taken place before it even got to a judge.
It's a sad situation all around but not as barbaric as people are making out.