There are many western democracies where there no single ruling party. 'The government' is made by an alliance of many different parties (eg: 25% + 15% + 10% + 5%.) They might share a common overall view of the world but each party can have a very different take on many subjects. The actual government has to do only what all of them agree upon, and the 5% party may have a disproportionate weight because that party leaving the government is as important as the 25% party leaving it.

So, the government is the people in the government and the small parties can be very vocal against it. Opposition from inside is a double edged tool to attempt to get more votes in the next elections, even from within the same coalition.