I can but echo some of the excellent comments made in #2. Certainly, I would disagree that the existence of government is for the sole purpose of looking after the interests of the middle classes. I would, however, agree that this is a legitimate view that could be argued, and that certainly history has shown that governments care a lot more about the interests of the middle class than they do about the working class. However, I hope that we are moving away from this and towards a form of government that is more representative for every class in society.
In this quote, Marx essentially argues that the state, as a political entity, does not consider the needs of everybody in society. In contrast, the state is only interested in the needs of the ruling class and, as such, it is a tool through which the bourgeoisie maintains its power.
On the one hand, the state does function for the needs of everybody in society. Consider the welfare state, for example, and there is clear evidence that the provision of welfare ensures that the needs of everybody in society are protected. By giving people a basic standard of living and free health care, the welfare state ensures that nobody is left in a state of need.
On the other hand, it could be argued that the welfare state is deliberately designed to protect bourgeois interests since it keeps people at a basic level of income. It also makes people dependent on the state for their basic needs. In addition, welfare is designed as a safety net for when people are not in full-time employment. As such, the ideological focus of the welfare state is to encourage people back to work and, therefore, to ensure that the bourgeois continues to make a profit.
So, to answer this question, it is important to look at both sides of the argument. Consider the various components of the state, like welfare and education, and look to see if there is clear evidence of bourgeois self-interest.