This was a government action, not an individual action of Sherbert. It is the action of the state of South Carolina and their denial of employment compensation
The Employment Compensation Commission negated Sherbert request for employment compensation based in the reason she was unable to work was a personal choice
Although the constitution permits legislature to create an exemption on behalf of Sherbert, the Free Exercise Clause requires only neutrality towards religion. Thus Sherbert's exemption would not be supported.