This poster attempts to push a stereotype that "smacking" parents just smack for every offence, and get more and more violent when that doesn't work. For most parents at least, this is nonsense.
Most parents use a mixture of different methods of discipline. They may say "no" first, followed by removing the toy / object, followed by a light smack, followed by time out for example, depending on how long the child misbehaves. Every parent and child is different. Some may smack daily, some may smack yearly. This stereotype is ridiculous and insulting.
What happens when a 'little smack' doesn't work any more? That's simple - try something else - for example time out or removal of privileges.
But if you won't smack, and time out doesn't work any more, what do you do then? It is the non-smacking parent who has fewer options, and is likely to have far more difficulty finding a discipline method that works for their child.