If they didn't want this, they could have just restricted it and it would have largely gone away as a topic of discussion, but current levels makes it inevitable it will become the main thing people think about
The reason immigration has cut through is it corresponds with people's own direct lived experience. It's not an abstract concept to people, it's visceral and real
Some politicians and certain parts of the media are blaming immigration for all of those issues. There's a constant barrage of talking points on the news and other forms of media. They cut through complex issues and appeal to 'common sense'.
People are directly feeling the pain. People are being given a reason for the pain. People feel that reason is the direct cause of their real pain.