re: Baloney
This Wikipedia article covers a lot of territory.
Multiculturalism can also be a prescriptive term which describes government policy.
In dealing with immigrants groups and their cultures, there are essentially four approaches-
Monoculturalism: In most Old World nations, notably with the exception of the UK [citation needed], culture is very closely linked to nationalism, thus government policy is to assimilate immigrants. These countries have policies aiming at the social integration of immigrant groups to the national culture. This is typical of nations that define themselves as one and indivisible and do not recognize the existence of other nations within their midst.
Leading Culture (German: Leitkultur): This societal model has been developed in Germany by the orientalist Bassam Tibi. In his book 'Europa ohne Identität' ('Europe with no identity'), communities within a country can have an identity of their own, but they should at least support the core concepts of the culture on which the society is based. In the West these concepts are democracy, separation of church and state, Enlightenment, civil society.
Melting Pot: In the United States the traditional view has been one of a melting pot where all the immigrant cultures are mixed and amalgamated without state intervention. However, many states have different language policies within the union. Immigrants maintain their own culture and family background while also becoming Americans.
Multiculturalism: a policy that immigrants and others should preserve their cultures with the different cultures interacting peacefully within one nation. Today, this is the official policy of Canada, Australia and the UK. However, contrasting views on the Australian model articulate a fundamental shift that identifies a singular homogenised culture derived from a heterogenous society. Multiculturalism has been described as preserving a "cultural mosaic" of separate ethnic groups, and is contrasted to a "melting pot" that mixes them. This has also been described as the "salad bowl" model.
No country falls completely into one, or another, of these categories. For example, France has made efforts to adapt French culture to new immigrant groups, while Canada still has many policies that work to encourage assimilation.
I would put the "Leading Culture" and "Melting Pot" categories together, with the implication that there are certain basic values in a free society that are not up for argument. For example, women as second-class citizens or outright property would not be good in America no matter which culture supported it. Outside of this, variety is the spice of life.
What is referred to as "multiculturalism" when political activists are talking about it, is Balkanization by any other name. Splitting American into competing ethnic groups is a good way to gain and keep political power, so some parties encourage this.
We are already seeing the results of this kind of social policy in Europe, and the immigration marches recently were making a point considerably different from the tolerance you're talking about.