When you pay minimum wage with no benefits, the talent pool is going to be severely diminished to begin with. Especially in Valenica/Santa Clarita, which has so many better entry level jobs to choose from with all the restaurants and shopping centers.
Even worse is that the best SFMM employees actually enjoy working there (mainly because of their coworkers), but have no choice but to leave because of the crappy culture and low pay.
That falls squarely on the park/company.