פירוש על עבודה זרה 43:1

R. Shimon b. Elazar allows one to rent the field to the non-Jew because if the Jew tells him not to work on hol hamoed, the non-Jew will listen.

The Samaritan will not listen to a Jew who tells him not to work on hol hamoed. The Samaritan believes that he knows more than the Jew, and in their system of laws, working a field on hol hamoed is permitted.