What do some people have against left-handedness?

I'm left-handed. When I was a kid, I lived with my dad for awhile. My stepmom always harangued me for eating left-handed at her dinner table. My dad got all bent out of shape one time when we went to play golf. He didn't want to go all the way back to the clubhouse to get left-handed clubs. When I went to school many teachers were so upset that I used spiral notebooks. I'd like to see them try writing in a binder left-handed, so they could see how easy it is. Some of them wouldn't even let me use a tablet. Therefore, I had to either write on the backs of the sheets. Or I would turn the notebook at a 45-degree angle and write sideways. People used to think that we were witches, demonic, or possessed. So what is it that some people think is so atrocious about being left-handed?