"The visas are meant for foreigners with specialized skills to fill discrete positions when Americans with those skills are not available. In the applications large companies must file for the visas, they have to confirm that no American workers will be displaced."
This case with Disney having US citizens train their H-1B replacements is a clear violation, and hopefully there are repercussions for Disney and Cognizant. (And more than just this: "Senator Bill Nelson, Democrat of Florida, has called for an investigation of the H-1B visa program.")