Do you agree that parents should never hit their kids no matter what the kids do?
No, but hear me out on this one; there is a huge difference between the kind of spanking I got as a kid (a swat or two on the butt) versus actual abuse, slapping them across the face, ect.
A spanking, when used right, can be extremely effective. My dad tried other methods to get me to behave as a child and sometimes it worked, but in the times when it didn't he would threaten a spanking. Now before he did it the first time I didn't believe he'd do it so I continued misbehaving and then he gave me two harsh smacks on my butt and put me in a corner to think about what I had done and why he had spanked me.
After that? If worse came to worse all he had to say was "If you don't behave I will spank you." and I pretty much instantly behaved for him because I didn't want to experience that pain again. But he used that threat only as a very last resort, and he did not ever have to spank me a second time in my life.
Many people I know had something very similar happen to them with their parents; it happened once, and once the threat was uttered they behaved and it was very effective.
My one friend who was never spanked was a spoiled little brat. Her mother let her get away with everything, including in the last years I knew her constantly taking her mother's credit cards and using them without permission but suffering no consequences other than having her mom take the cards back and tell her not to do it again.
So yeah, if other methods don't work I think it's perfectly fine to result to a spanking and then use that as a last resort threat in the future as well if it means the child will behave. Because I think a lot of kids these days suffer from a lack of punishment and consequences for their actions; I've seen so many kids in public throwing tantrums or otherwise doing shit I never would have gotten away with and instead of punishing them the parents just put up with it and tell them no for a while and then give up and let them do whatever and it's honestly more annoying than anything.