Calico is suggesting she was born in Bangladesh. If that's the case she is dual nationality and Javid is revoking her British nationality first.
If she is not dual nationality then Javid cannot revoke her British nationality.
Re the baby, it's definitely(?!) hers, not so definitely the Dutch guy's. Highly unlikely that the birth is registered anywhere. Its nationaliity is therefore unclear and disputable. British, Dutch, Syrian, Bangladeshi or some combination of those four could be a possibility.
What's clear is that Begum was a child victim of brainwashing and radicalisation before leaving the UK, and she is still. Blaming her for her current state is, to some extent at least, blaming the victim because she is to some extent a victim - she was radicalised as a child on our turf. If, instead of radicalisation and leaving the country, she had been sexually abused and was now working as a prostitute in the UK, perhaps people would see that differently.