Fam all Somalis in Somalia are Muslim.
But did you it's usually the West that brainwashes Somalis into leaving the religion.
I think you're correct on the fact that the vast majority have a belief in Islam that unwavering but poverty, lack of access to other forms of information and the severe social sanctions for not being a muslim all contribute to over-stating the seize of Somali muslims.
In fact many could be better described as deist with islamic leaning, as they fall short of the requirements or perhaps subscribe to more vague interpretation of Islam that differs greatly enough to be a distinct belief in God with islamic sourcing.
Furthermore many are what we call "atheistic muslims" meaning people who out of fear or comfort comply with religious commands in public but hold no such belief.
Therefore to categorize all as sincere believers of the Islamic faith is simply naivety.