Let's be real Most Muslims live around Muslims and in the context of somali girls they have been culturally at the very least been brought up not to be promiscuous. So even if they know nothing about the religion. They were still fully aware of the consequences of there actions and that it ain't exactly something they would do openly unless they grew up under messed up and unique conditions.
I have known many non-Muslim ladies in the West far more modest, if moral and ethical than some Muslims I have encountered in Muslim nations in the Gulf, NA, and Asia to name a few, of course the numbers are skewed, but the point stands that current crop of Muslims are not quite what their predecessors once were; case in point, the filthiest lass, in deed & mind, I have ever come across was from Kuwait.
Adjunct:
An old mate was to marry a lass from Maghreb, both being of the same extraction, (his being brought up in London, with her being from France), and a week before the wedding, his future MIL asked him 'if he truly knew of her, and what she had done for a living, in the past', bearing in mind, the lady sported niqab and the works --- to cut a lengthy story short, it turns out she was an enscort in France. He flipped, calling off the wedding. Now, let us call him 'I', he was a rogue of the worse form, but a decent lad; do you think he should have called off the wedding?
Unto you.