The difference is the pet would have been returned to it’s owner, or merely walked home if not killed.
Right now she is facing charges, and perhaps loss of her license, evidently using the excuse it was on her property isn’t as solid as you think.
It is especially weak for a woman who wants to work as a veterinarian, and win community support.
Sure, if you knew who the owner was. But it was neither tagged nor collared, and since it wasn’t mentioned (or I didn’t see it) I doubt it was chipped. The cat would have gone to animal services, done it’s time and then been put down either by gas or overdose.
That she could lose her license over this is ridiculous.