Temporary workers on H1 and L1 are required to pay social security and medicare taxes. Typically the temporary visa is intended to the extendable till 6 years. So unless the temporary worker receives permanent residence or US has signed a treaty with the home country of the worker the immigrant worker never receives any benefit for the tax paid.
In case there is no treaty signed with the home country the immigrant worker should not be asked to pay social security and medicare taxes as they would not receive any benefits from it when they return to their home country before working in US for 10 years.