Then they should have called someone who does. There are vets on call all the time, including government vets who deal with animal welfare. There are also local authority trading standards inspectors who also deal with animal welfare and could guide the police to someone local who would have known what to do.
And as a vet, I can confirm that the links between animal abuse and domestic and other kinds of violence are very well established. Any policeman who could do this (and I’d be willing to bet the driver was male) he should not be ever put in a situation where he has power over anyone.
Comparisons with shooting the animal are irrelevant. That would require higher level decisions and professionals coming in. It would be unlikely to be deployed anyway as it wouldn’t be safe in a built up area.
Whether it would be enticed with food while so worked up is impossible to say, but there is no doubt that the action that was taken was entirely inappropriate. Quite apart from anything else, had the animal gone up onto the bonnet of the car, the driver and any passenger could have been killed. Given the recklessness of the action, it’s a miracle it turned out as well as it did. It was entirely down to luck and not skill.