None of the things by themselves fully justify "belief" in a religion yet many people claim they are without a true belief in the entire system. It's the problem with such a vague question. By a narrower definition very few people attending a place of worship are true believers. Someone can believe in god, but not really believe in the rules, and still say they are "religious". Someone can believe in the rules, but not god, and say the same. I think if you are practicing the religion to some extent then you have a right to call yourself religious if that's how you view yourself regardless of your true beliefs on god, rules, etc. Cultural impact matters more than we give it credit for.

Another big reason is reason number 4

4. Gives a sense of community and cultural connection that other things don't quite provide.

I've met a not so inconsequential amount of people in my life that when pressed admitted, they don't believe in god, don't believe in the moral teachings, but attend a place of worship because they think there is no replacement for the interwoven community and cultural connection their place of worship provides. Many people simply like the community connection of their root culture. This is especially true in minority groups (black church, synagogue).

They are just trolling, they are looking for the argument for arguments sake. Look through their post and comment history. Report, down vote, and block, then move on.

I've never much cared for the details of a lot of communities/subs outside of very specialized ones. I'm going to participate if the topic is interesting and learn about the rules as I go. There being multiple communities for the same thing was pretty common on reddit.

Related question, why the fuck do some people feel it necessary to grunt, moan, pant, and otherwise loudly vocalize while shitting? Zero people want to hear you, shut the fuck up, you are gross.