Predictive policing has the ability to be great if....
Sadly it is true that certain sectors of society are more likely to be sucked into crime, and especially gang crime. Typically young men from lower income households with lower educational attainment, and lower levels of aspiration.
The issue here is that instead of looking at 'young men who are poor, not doing well at school, and don't see a good future' (which is really difficult to profile) the algorithms take the easy way out and do a match with 'young black or muslim men'.
There is nothing inherently less aspirational, educational, or attaining about any particular genetic inheritance - but there may be about certain cultural groups, and how those groups have integrated (or failed to integrate) into UK society. Algorithms have a distressing tendency to jump on the back of easily identitfiable statistical factors, which may 'work', but which will exacerbate the underlying issues by objectifying and victimising groups which have already experienced significant negative bias.
Sadly unless society (or its proxy, Government) makes a concerted (for which you can read 'expensive') effort to actually address the underlying issues the problems will continue.
A rather interesting study into educational attainment in I think South America showed 10% better education, incomes and attainment now in communities clustered around the sites of educational religious missions 200 years ago. No such positive affect existed around doctrinal religious missions. These affects are long term, and persist long past the original causes, unless positive action is taken to correct problems.
Predictive policing is coming, and it will reduce crime, but it is the challenge for society to ensure it doesn't do so by making it even harder for those who are suffering under current systems to improve their position in society.