Intolerance can only be defined as a beings unjustified objection to accept the views, beliefs, and/or behaviours of others. In other words racism, sexism or prejudice of any sort is usually the result of ignorance. It is also true that anything living, fears what it can not understand. Thus prejudice is also a result of fear of the unknown. This is the key reason as to why 'open minded' people have more tolerance, they are not afraid to explore and see what they might discover. Tolerance is the core value of western culture. Everything known to be true about democracy etc. would fall.
Prejudice leads to hatred, which leads to violence, which in turn results in war. Social harmony is dependent on tolerance. It was 'J.S Mill' who said that "tolerance was of fundamental importance to the individual and society". Absolute tolerance is both vital and impossible. This is evident when religious or moral groups have conflicting arguments and believe that there is no alternative except violence and total retaliation.
However there are certain arguments against toleration, censorship being one of them. Censorship is a controversial argument, one might believe that what a person watches or believes, and how a person conducts their personal life including sexual relationships is a matter of individual choice. If society is unharmed in the political sense then we can coincide.
However others believe that a society must be bound together by a common culture so as to not decay our shared beliefs. In other words we must conform or absolute anarchy will reign. This really becomes a matter for the liberals to answer. However I am sure they would agree that conformity is not essential and might even raise an argument for it. I certainly believe that non-conformity can only lead to a bloom...