Collectivism gives priority to the welfare of a group over the welfare of an individual. We all do that sometimes as the group consists of many individuals. Soldiers killed in battle are sacrificed to the nation, for example. Social democrats and liberals are generally far less inclined to go to war than Conservatives but most accept the need for some type of army.
Conservative family values can mean that weaker members of dysfunctional families are left unprotected while Conservatives try and pretend the problems in those families don’t exist. Christian Conservatives fight against health measures to prevent AIDS and other types of STD because they hope people will fear these diseases and will stop the type of sex that Christians don’t like. Innocent victims of these diseases like babies born to infected mothers don’t seem to count. Despite such cases Conservatives don’t like to see themselves as collectivists.
Collectivism is more often associated with Communism. Under Stalin any number of Russian workers were overworked and died from that in an effort to build the great Socialist utopia. Similarly in Maoist China any number of Chinese peasants starved to death due to failed policies during the so-called Great leap forward. In reality under Communism the subordination of the individual to the collective becomes subordination of powerless individuals to the party and the dictator. Right wing dictators also mistreat powerless individuals.
Liberals and Libertarians prefer individual freedom though freedom under libertarianism can mean freedom of the strong to oppress the weak. If libertarianism were accepted weak individuals would face arbitrary dismissal by powerful employers without welfare to keep them going afterwards. Fortunately that hasn’t happened even in the United States but if that ever happens the victims of the Libertarian society will be sacrificed to Libertarian principles.
Social Democrats and Democratic Socialists are more interested in collective welfare than people who are less far to the left but both groups favour protecting weak individuals from powerful people or groups.
Liberals and social democrats both value personal Freedom, both accept the need for some regulation to protect the community. Liberals give more eight to personal freedom, social democrats give more weight to regulation that they hope benefits the community.