Its not about giving her citizenship, she already had it from birth but had it stripped away under the pretence that she could get Bangladeshi citizenship (which they dispute). This is essentially the UK trying to dump its problems elsewhere and setting the awful precedent that if you have recent ancestors with another nationality you can be stripped of the one you were born with.
By all means punish her, lock her up for 30 years for all I care, but trying to pretend she isn’t British and foisting the problem elsewhere is disgusting.