You seem to be fixated on the theory that this problem is brought about by something called political correctness. It is not and you don't seem able to grasp that or are unwilling to.
Pure political correctness means treating everyone the same. Not to grant favours or discriminate against any class, creed, sex, religious belief amongst other character traits. Here is one definition:
"The avoidance of forms of expression or action that are perceived to exclude, marginalize, or insult groups of people who are socially disadvantaged or discriminated against."
Taken from:
Oxford Dictionaries - Dictionary, Thesaurus, & Grammar
And the police constables oath includes: "........... fairness, integrity, diligence and impartiality, upholding fundamental human rights and according equal respect to all people..........."
The police notionally serve the monarch of the day. But in reality are an arm of the government of the day. The government are responsible for making laws. If you want laws changed then canvas the government, not the police.
Where the law has failed in the case of EEs stealing fish or Asian men grooming young girls is that the people responsible for dealing with all cases impartially have not because they have
not been politically correct. You don't seem to be able or are unwilling to grasp that.
There has been a tendency to shy away from investigating minority groups for fear of being branded racist and at the same time also granting immunity to public figures such as Cyril Smith and Jimmy Savile. That is not being politically correct is it?
Political correctness is a theory nicepix, a theory that has been put into practice (according to wiki how.com which I linked to earlier on in this thread) since the 1970's.
Political theories (like communism, socialism and marxism just for example sake) need societies as testing grounds, being a social engineering project, the first intent falls on first changing the minds of those in such societies that are not prepared for, nor have a defense for any effects that have a negative impact on that society. I really do not need to prove that by repeating what I have said already and brings us onto the point of law. The fact that you admit there is a problem shows very clearly that PC is not the same as law and since one followed the former (PC came after laws had already been made regarding rape and theft) shows what has been playing the largest part of all increases in confusion or knowledge of law in such serious cases of late, this can be called corruption, but all in all all these things can be narrowed or boiled down to a transgression from the law (in my opinion aided and abetted by PC).
So according to your first example you quoted, as long as you ARE the marginal or socially disadvantaged group you should not be discriminated against, PERIOD. Leap frogging the interests of the vast majority who in this theory are silenced completely, how ironic for democracy also.
Now ask yourself where the law is serving as a punishment to ALL who allowed the rapes to happen (do also include the political theorists who served immigration to the British undemocratically right through to those who turned a blind eye and those who say they maintain our laws). Then ask yourself how the law will deter others from doing the same and why or why not as the case maybe.
Your second point that you insist I cannot grasp relies on why someone would be discriminated against in the first place or disadvantaged. If I leave my country to sponge off of a better one that is self inflicted, the notion of asylum goes beyond finding the nearest safe place in the majority of immigration cases as its the indigenous that stand to lose what they worked hard for, so that is yet another guilt trip I cannot subscribe to either.
PC protects quite a few things that left untamed will destroy whole countries, uses arguments that on the surface are hard to oppose, are completely irrational often playing on the emotions rather than the logic in foresightedness or agreement of the vast majority of such a nation.
Plenty of examples walking the earth now who can now promote what is now protected from discrimination.
Someone who is in a minority but chooses to rape a women should be expected to be discriminated against, or a step further, punished or disadvantaged by forfeiting their liberty, you cannot seem to grasp that for these people to of even had a chance to commit such a crime in the first place relied on the help of the definition you gave for PC.
The "constitutional monarch" is we are told, simply a figure head for democratic government, but in a bizarre twist of logic, the oath she swore was to the God of the bible during her coronation, so right there already is a conflict of interest on her part and as she gives royal accent to man made law (which last time I checked the bible prohibits man made laws in the Decalogue) she may even be suffering from the potency of her power as her empire crumbles, also self nullifying her own subjects justice for business interests via a justice system. Her coronation oath contradicts "pure" PC theory, only saying.
The master of the police is on the police badge and uniform, period.
The people always come last. That is why PC in its "pure" form protects every perversion that the good laws that helped build civilization gave protection against, this is the part you cannot grasp.
To answer your last question just ask yourself honestly why the law could fail in such a disastrously epic fashion.