Why is spanking an issue with people?

When I was a kid and stepped out of line, a slap to the leg and I knew better not to do the previous thing I did again. I wasn't a bold kid. Just the odd tantrum because I wasn't getting my own way. Slap to the leg and off I went. I had a horrible thing for biting people, again, I was 2, just the same as being a little **** at times and so, my parent bit me back one day. I took my biting too far and left a mark on my parent. After they done it back, I knew better than to do it again. It wasnt abuse. There was no abuse when I was growing up. It was basically "don't do it to someone else if you don't want it done to you". My parents were hilarious when I was growing up. The odd slap didn't make them bad parents. My nieces and nephews growing up got the odd slap on the legs. My partners parents would do the same. It's the same as the wooden spoon being hit against the kitchen tops and you knew to leg it out the door and back out to your friends or up the stairs and hide. Wait 5 mins then it's forgotten about. People are afraid to punish their children nowadays because breathing is just about tolerated before they get reported. It's becoming a joke. My nieces now, don't get any form of punishment when they have been acting up. Apparently the bold step is not allowed anymore. Telling a child they are being bold isn't allowed anymore. According to my nieces creche no form of punishment is actually allowed. So what then? Teaching a child right from wrong is a form of parenting but where do you draw the line at abuse? We all got the odd slap here and there.