humane treatment for farm workers act

On Sunday, Gov. Jerry Brown rejected The Humane Treatment for Farm Workers Act – authored by Assemblyman Charles Calderon (D-Whittier) – that would make it a misdemeanor crime, punishable by jail time and fines, to not provide appropriate water or shade to workers laboring under high heat conditions. The governor also vetoed AB 2346 – The Farm Worker Safety Act – by Assemblywoman Betsy Butler (D-Los Angeles). It would have allowed workers to enforce the state’s heat regulations by suing employers who repeatedly violate the law. The United Farm Workers strongly supported both bills.
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United Farm Workers email

Uh, what was the logic behind that decision?