We started really early with my son on this one as this type of thing is a very big deal to us. If he does some behavior that we don't like or feel is inappropriate we immediately stop him, get down to his level, get eye-to-eye with him, hold him by the shoulders and say a firm, "No. We do not [whatever the misbehavior]. Tell [whoever] sorry for [whatever the misbehavior was]." We don't say it in a soft voice and we don't yell. We give the "cold, hard, stare" that means we mean business. If our son sees this look he knows that he'd better behave--it is rare that he sees this from us.
My 11-month-old has developed a habit of throwing her head back when she doesn't like something in a tantrum-like way and even though she is 11-months-old we correct this behavior. We tell her, "No. That is not okay." again with the same, "cold, hard, stare." She gets the point that we're not pleased with her behavior. Sometimes she will cry because she has been corrected and is not used to us using a harsher tone and look with her--she knows it's for real. She knows she's being disciplined--even though she's only 11-months-old and can't speak in sentences yet or even walk.
By 19-months-old if your child is verbal at all, he should get that what he is doing is wrong and he needs to be made responsible for his actions and apologize. You should expect him to speak as much as he can in an apology. If the only thing he can say is "Sorry. No hit" then that's what he says but it's very important that you get this under control now or you're going to fight it in the future. Seems he may already have a habit developed.
I wouldn't have breastfed him unless the issue had been settled properly. To me "ignoring" children (turning your back) is a form of discipline used a lot in Hong Kong that is pretty ineffective. I see a lot of parents get angry with their children in public for example and the children are throwing a fit and meanwhile the parents are standing there turning their backs trying to "ignore" the child hoping it will stop--it usually only escalates.
It seems to me in your situation the issue was not resolved. It was sort of a passive-aggressive stand-off between you and your son. Now, if the child had been directly corrected and had taken the correction to heart and had said sorry and all was forgiven then I would have gone ahead with the breastfeeding. I see the breastfeeding as similar to giving a hug. If the child is still being naughty and hasn't properly understood the lesson and apologized why would one give a hug--it sends a confusing message that the behavior is okay. Hugging after the issue is resolved only seems natural, though.
In our case, if my son were corrected for hitting us (which he would not do because he knows absolutely that this behavior is not tolerated in our home--actually he has never hit us in anger like you described because he tried it once with our helper and he was corrected and really never tried it again--we don't reason with him or try to use logic in this instance--absolutely not tolerated) and he continued to throw a fit and not respond to the correction he definitely would have had something like this said to him in a very strong tone, "You DO NOT HIT your mama and dadda. That IS NOT OKAY." I would have then removed him from my bed and put him elsewhere as a punishment. I just don't tolerate that sort of thing. That would be a serious issue to me.
