It makes a point, but doesn't judge
I just watched this film and wanted to see what everyone else thought...and whoa! A lot of hatred. Before I get into the social commentary, I really liked this as a scifi/horror film. It was well directed, beautifully shot. The 'monsters' weren't shown too much which added to their scariness. It was atmospheric and tense. Now, onto the big point of contention, about making villains into the heroes.
Firstly, this isn't the first or tenth film to do this. It borrows heavily from Assault on Precinct 13 which has the criminals join forces with the police to help protect themselves. That film particularly had a lot to say about societal breakdowns and criminality in the 70s. Then we get more modern films like Pitch Black, with Riddick saving the day and even spawning sequels, games, anime all dedicated to a criminal.
I think why people have a problem here is that we see our bad guys being bad, without really having real remorse. Previous films sidestep the issue of actually showing us the misdeeds. Only giving us snippets of backstory or having reputations. So, it's easier for us to root for them and believe in their heroic acts. Maybe they've been misunderstood heroes all along, the writers want us to think.
But, in Attack the Block, the first scene is showing us what bad guys they are. And for me, it's a more honest portrayal. Cornish was trying to recreate an incident he had where he was mugged and admitted that the kids mugging him were scared too. And we can see that here. Later, when Sam talks to Moses about the crime, he says he wouldn't have done it if he knew her. And actually rescues her later on. This of course doesn't make any of it better. The point here, and another character criticizes Moses for, is not thinking about the consequences of his actions. His brutal attack on the female alien, is why the aliens come in full force. But I think Moses at least recognises this, which is what motivated him, and him alone to risk his life when blowing everything up. Cornish is not admonishing them of their crimes, just showing us how it exists. And I guess my biggest criticism, is that there aren't really any consequences here. I like that they get arrested at the end, but I wish Sam hadn't jumped to their defense, or to have the block celebrate Moses as a hero. They resisted arrest, and I would have liked Moses to accept his punishment at least more vocally. I didn't want to see a 360 degree turnaround. That wouldn't have been true to character or to the film. But an acknowledgement that a change needs to happen would've been nice