Notice that "Specialty Occupations" are all jobs that Americans are capable of doing but which Congress has decided should be done by foreigners:


http://www.immspec.com/h-1b-visa.htm

Details on the H1B Visa

(Specialty Occupations)

Common positions that fall under the H1B Visa category are Physical, Occupational, and Speech Therapy, Engineers, Doctors, Pharmacists, IT Professionals, Management Professionals, Sales Force, etc.

Definition of H1B Work Visas: The H1B visa is a non-immigrant category established by USCIS (U.S. Citizenship and Immigration Services) to employ international workers with specialized training. H-1B work visa is generally set aside for foreign workers in "specialty occupations" and fashion models of "distinguished merit and ability." The aliens employed under this employment-based immigration category may be filling permanent positions (“USA Green Cardsâ€