While I'll admit the video makes me cringe, I don't see that the judge was wrong. They had proof of one instance. Is that really cruelty? Ongoing and repeated behavior of what was on the video, but they had one.
And let's face it - after Lyle stumbled across the first instance, you better believe she poured thru the rest of the security tapes and found zip, zilch, nada or it would have been made public just like the one they found.
The former employee was mean, and stupid for doing something like that with security cameras. But I agree with the judge, one instance wasn't cruelty.