I wrote on my hand “I hate (my teacher’s name).” Why am I getting in-school suspension (ISS) for it?

It’s very heavy handed, and a sane school would say that because your hand has that writing on it it can be caned, but not make a big deal of it. However some teachers are very sensitive and easily upset, and it destroys their image of themselves, and so they are lashing out with this excessive punishment. But whilst personally if I was your teacher I would just laugh, it is very provocative, and you can’t expect not to be punished for it. But caning tops. Suspension is way too much.