It's more that the average Brit finds a way to be upset about everything any UK government does. Even just the test of the cell emergency alert system was met with fierce public criticism: what if people crash their car out of surprise?!
But being critical of your leaders isn't the worst thing in the world. It's fairly bipartisan too; most of the people who voted for our current PM just a year ago now disapprove of him. A high level of public scrutiny on one's leaders' is probably quite effective at preventing totalitarianism. Whatever can be (often justifiably) said about our ineffective leadership, what we do have is a good track record for stability.
However, sometimes it's really just cynicism for cynicism's sake.
