Before you ask 'why', ask 'if.'
"If is it so important to break someone else's faith?"? ;P
It's not it is just fun. Albeit admittedly it does get a tiny bit boring over time however thanks to ignorant Atheist who want a religion desperately we have SJWs who put all other religions to shame and even flat earthers to an extent. I guess since most SJWs are twice baked religious people it makes them twice as dense.
To whom is it important? Not me. Everyone needs to decide for themselves what makes sense in this crazy world. If what they have decided works for them, I'm happy they found what makes them happy. It doesn't need to make sense to me or make me happy...I don't even care if they want to tell me about their happy...just don't impose it on me or others.
I think it's not important for the vast majority of us. Most serious pushback against religion happens only when it affects public policy, education, science research, and so on. There are exceptions, of course, as there will always be people who want to impose their will upon others' private lives — though I'd argue that we see less of that in general from secular people than from the religious (but that's only from personal experience and may not be universal).
Seems like most of the people on this site have left religion behind. There is probably some inclination to help others to get away from religion. I look at my leaving as part of a path of finding out what I really believed. After I left, I could tell you in great detail what I didn't believe. And just a little of what I believed. Have been searching for what brings truth and meaning to my life for a long time. I don't feel like it is up to me to break someones faith. They will have to see the light on their own, if they ever do. I do not want them to intrude on my life with their faith. If they can keep it to themselves, then fine.
It's not. I abide by the saying "live and let live". If someone has elected to believe in a higher power, an afterlife, heaven and hell, or Bigfoot, it is entirely their prerogative. In the same vein, I'd rather not have people attempt to convert me to their beliefs, so I say it as soon as someone drops the "Jesus is good and yada yada" line by gently informing them of my atheism and asking them to respect my personal lack of faith if they wish me to respect their beliefs. It doesn't always work, and has in fact made people try that much harder to guide me to Jesus, but at least I can say I made an effort.
I think it's best to let someone see the light on their own That's how it was for me.
I am happy to leave folks to their delusions as long as they're not trying to sell it to me.