Yet you believe most of the “stories” about religion.
Do we? I certainly don't. I don't know anyone who does, atheist, Christian, Muslim...
You wouldn’t say these things to someone who believed in Islam, Christianity or Judaism
Of course I would, and I have. If someone looked me dead in the eye and told me that Jesus actually turned water into wine, or Moses parted the Red Sea, I would tell them that was plainly nonsense.
I certainly wouldn't criticize someone for simply following any of those faiths, living their lives in accordance with their teachings etc. Infact I admire people who have the strength of character to stick to them.
But completely ok to bring someone down for their beliefs in spells
Spells aren't real. You can't cast spells. I'm not bringing anybody down by pointing that out. If I believe with all my heart that I can fly, tell everyone I know that I can fly, and find a community of people who will reinforce that belief, it doesn't change the fact that I can't fly.
If you're obsessed with someone to the point you're 'casting spells' to help/inconvenience them, for example, you will surely notice something nice/inconvenient happen to them at some point, but correlation is not causation.
To go back to your point about 'You wouldn't say that to a Christian/Jew/Muslim', I consider it no different to someone praying for an illness to be cured, having medical treatment and crediting the recovery to the prayers. You can believe it all you want, but that doesn't make it true.