Two basic propositions to choose from.

Liberty or Collectivism.

There is no compromise to be had between the two, else collectivism will expand at the expense of liberty.

So what's wrong with collectivism?

Let's begin by defining the term.

Collectivism is the theory that production and disposal of wealth should be controlled by the people collectively. At the extreme you have communism. On the path to that  extreme it is called socialism. Because explicit socialism has lost its appeal in recent decades, other terms are frequently used as a cover: communitarianism, economic democracy, Democratic Socialism, etc., but whatever you call it, it's collectivism.

What most people don't realize is how much the U.S. economy has been socialized. Considering that government is the agency of collective action, the U.S. economy is nearly 50% socialized (or collectivized), that is, controlled by government. 

Back to the question: what's wrong with collectivism?

1. Conflict. To begin with, there are many flavors of collectivists. They disagree with each other on many particulars.  The left-collectivists have produced many splinter groups.  Right-collectivists are somewhat less factional than leftists, but have major differences with the leftist orientation.  This is amply illustrated by the major collectivist parties in the U.S., the Democrats and the Republicans. If you don't think the Republicans are collectivist, note their support for major social programs such as Social Security and Medicare. There are some distinctions between the two, with Republicans tending more toward cultural collectivism while Democrats tend more to economic collectivism, but both parties are collectivist.
   
   

2. The problem of political power. Lord Acton said that "Power corrupts and absolute power corrupts absolutely." Proponents (or carriers) of the leftist point of view believe the source of corruption is corporate greed, a view which is a product of their Marxist heritage, and while it may be true that corporations often participate in less than honorable activities, history shows that corruption is a problem in any political system, from the ancients through today. The lesson of the Soviet Union proves that corporate profit making is not a criteria for political corruption. In fact, the USSR (Union of Soviet SOCIALIST Republics) offers many lessons on the shortcomings of collectivism. 
   
   Political power is a corrupting force, the implementation of which is essential to enforcing the strictures of collectivism. You can't have one without the other. I challenge anyone to cite an example of any political structure that has no collectivist aspect or any collectivist system that does not have a political structure coexistent. This brings us to another definition and a final conclusion.  Fascism is a political philosophy that advocates obedience to authority, it is authoritarian.  Fascism was the explicit goal of Italy's Mussolini around the time of WWII, and is commonly viewed as the mainstay of the NAZIs (Nationalist-Socialist).
   
   Fascism is advocacy and implementation of political power. Political power compels obedience by threat of physical force. Collectivism works by compelling its subjects to operate within collectivist strictures.  Collectivism is, in all of its forms, fascistic. Advocates of socialism and its ilk may deny fascist, but how else do they expect to collectivize everyone except through political compulsion?  Collectivism opposes freedom.
   
   

3. Performance.  The foundation of human societies is the production of the wealth that people consume.  Any economic system must be judged by its ability to produce the goods.   Economic collectivism has a very poor record regarding this fundamental task.  Prior to the communist revolution in Russia, that country was an exporter of wheat, after the revolution, Russia became an importer of wheat for the duration of the Soviet regime.