Why are people who believe in horoscopes often targeted by trolls on Q&A websites?

I'm not sure this isn't two separate things.

I do not believe in horoscopes - I am not superstitious - but although I am not sure what is a "troll", I don't bully anyone for doing so.

Some [anti?]-social media users are just bullies and they will find anyone to attack because it bolsters their weak egos. I doubt the subject matters - they are just bullies..

People who believe in horoscopes are often targeted by trolls on Q&A websites because some view astrology as unscientific or superstitious. This can lead to mockery or criticism from those who prioritize scientific evidence and rationality over personal beliefs and spiritual practices.

Not all who reject astrology are trolls
Perhaps it is because it is based on a false premise, and thus supports increasing ignorance
Not like it’s a religion,
Just a toy really
Some say it supports bigotry,
So maybe that’s why they get emotional

I didn't known they are, but I suspect if you asked the bullies most would be totally unable to explain their actions.

It's not just believers in horoscopes that are targeted by trolls!

Why is anyone targeted by trolls on any websites?

I don't know.