Sounds familiar... didn't half the western world just do that to Iraq?
Certainly did. Which is why most of the non-Western World are unhappy with that half of the Western World, and around half of that half of the Western World are unhappy with the lying bastards who have shamed their countries by doing it.
And similarly here - most of the Muslim population of the UK are unhappy with the police for their actions against their racial/religious group, and around half of the rest of the UK are unhappy with the police who've shamed their society by behaving in that way.
In other words, as the people who set and enforce compliance with laws, the police are supposed to follow those laws scrupulously, because otherwise it becomes a "do as I say, not as I do" situation where the police are just another gang of thugs. Similarly in international terms, if the leaders of countries like the US and UK want to be the "global policeman", then they'd damn well better be following the laws themselves before they start casting aspertions (and bombs and missiles and soldiers) at the leaders of other countries.