I hate-stalk my step sister on social media
That's awful. How does that make you feel?
It makes me feel much better when my step sister feels bad.
Stalking someone over social media is wrong and is especially so when it is a member of your family. You should support your step sister and not try to cause her any harm. If you take pleasure in causing her emotional pain, you need to figure out the issues behind that behavior and try to resolve those issues.
I don't know why it's wrong. I'm confused, what is wrong with it? I just love looking at her pics and reading the negative responses from people.
If you enjoy that then there is a lack of empathy here. It's not normal to enjoy watching people get hateful responses.