The original comment is a reference to the Muslim religious figure Mohammed and his 9 year old slave girl he raped "wife".
And to stave off any claims of racism, no this has nothing to do with region of origin, religion, or skin color and everything to do with the fact that a 9 year old can't consent to anything, and she wasn't exactly romanced in a traditional sense.
While this is atrocious, I suggest that you look at the laws regarding child marriage in the United States because you might actually be able to influence those. Four states have no minimum age. Children as young as 10 have been married in the United States in the past 20 years.
As we are all watching in real time, religious conservatives have no value for women except as breeding property. Doesn't matter the country.
Not that I'm advocating this scenario, but can you imagine hearing your neighbor "married" a fucking child? Is this not why we used to form a posse to definitively say, absolutely the fuck not? By which I also mean finding said child's "guardians" to throw on the pyre.
I assume, of course, that religion is involved in their disgusting rationale.