These stores host flock and other cameras on the premise of: it deters crime, decreases theft, shoplifting, and other criminal acts and is a net benefit on that basis. Privacy makes them no money. As far as they're concerned they'd put cameras in your cars and homes to make sure you're not stealing from them.

You have to break that calculation so it costs far more than it can save to host these. Cutting down cameras doesn't incur anywhere near large enough a cost to change that calculus and there's a good chance Flock pays for the new cameras not the store. A boycott would be hard to get them to acknowledge as being connected to their hosting these kinds of surveillance systems and the people who put them in and keep them there would try to strongly deny a correlation so it would need to be a militantly disciplined, well organized campaign.

The problem is you need the media to help you organize such a widespread and well-telegraphed in message boycott campaign and the media is fully on the side of Flock and regarding any vandalism of Flock and similar ALPRs as a case where they desperately want the person caught and will air their photos to attempt to help catch such a criminal monster. So the media would never broadcast such a campaign, would never even acknowledge it. Local news makes so much money off police stories, local crime fear-mongering, etc.

Of course there are other options to change the cost calculus but they're not preferable due to legality issues.