Nothing is very clear at this point in time. Might have to get one of the kanjars interviewed personally and try to get inside their heads. But at this point in time, it looks like the individuals who get involved in these crimes are mostly petty criminals, motivated by the same crap that your average criminal is. But how and why they take that leap from petty criminal activities to grooming and prostitution and targeting vulnerable young white girls is something that can't really be established. I know they don't target non white girls that aggressively because for all our faults, ethnic minorities do keep an eye on our relatives to make sure some one isn't targeting them and there is an extended family system that would usually prevents from such young girls going in to social care etc.
The exact nature of their mentality is something that needs to be deciphered so we can combat this more efficiently.