Why my parents have never accepted that I got tattoes on some parts of my body, on my arms or on my legs even over 18 years old

Once I came home with a little tattoe (a little flower) on my right hand. When mom and dad glanced it they became extremely angry, They berated me for my irresponsibility and my thoughtfullness. My dad was so infuriated that he ordered me to my room and to prepare myself for a sound spanking. I was almost going to 19 and I didn't understand why I was spanked and especially why it was forbidden to be tattoed on his body. I was also grounded for two months and, supreme humilation,put back in short trousers in order to prevent me from going out at night. Although I looked younger than my age, I was ridiculously too old to wear short pants