I very much agree with what you say on automation bias.
Certain technology just has too much potential to be misused / people repeatedly prove they can't use it properly. It also comes with risks of making authoritarian takeover easier.
However, here, it seems they used Flock a bit like a regular ANPR. The actions they took independent of Flock show there are better stories to use to criticise this technology.
And if your country happens to have a police force that is historically bad at its job, giving them that power seems like a really stupid idea.
¹: https://en.wikipedia.org/wiki/Automation_bias