California grows tomatoes. Trader Joe's in California sells tomatoes from Florida. Californians are protesting at Trader Joe's to raise prices on tomatoes.
Is this protectionism? No.
The protesters feel the farmers do not make enough money. The idea is to make the point of purchase charge more. The extra money can then go back down the purchasing chain to the farmers.
There's no chance that the POP or anyone else in the supply chain will want to keep the money for themselves, is there?