That has absolutely no basis in the law. Yes, the stadium is publicly owned, but it is leased by the Seahawks for their games. As far as I know, the State of Washington has no role in ticket sales or policies, and does not benefit from such sales. The fact that it is a publicly-owned stadium does not mean that the team cannot decide who can/cannot buy tickets to the game.
Actually it does. The State cannot lease their property to companies that violate public policy. I am sure that the contract contains equal access provisions and other clauses that would prohibit them from engaging in discriminatory ticket sale practices.
In this case by deliberately denying access to Californians to a public arena owned by the State of Washington, there is a violation of the privileges and immunities clause as enunciated in Sáenz v. Roe, 526 U.S. 489 (1999), specifically "the right to be treated as a welcome visitor rather than a hostile stranger".