"Is it racist to consider aspects of anyone's culture?"

No - but you haven't "considered it". You have generalized about it and seemingly defined it, and your definition of it has so far been informed by apparently received knowledge about how this culture expects British Pakistanis to behave, and by the words of Jack Straw and Anne Cryer.

There are some British Pakistani Moslems who live according to strict orthodox and conservative values, and who expect other British Pakistani Moslems to behave the same way.

Of those, in extreme cases there are even some who commit domestic crimes against women.

But they are not representative of British Pakistani culture.

There are also Gangs of paedophilesm some made up predominantly of British Pakistani heritage, though not wholly.

These gangs are driven by a motivation that I do not understand.

All members of these gangs are committing crimes against young girls, whether those gang members are white or British Pakistani.

The white gang members are not driven by the value systems of any kind of Pakistani culture, and neither are their British Pakistani friends within the gang.

One thing however that they do have in common, is that they live in a society where men and women believe that if a young girl dresses like a slut then she "was asking for it".