First of all, Christians (maybe even Protestants in general) don't have bishops and stuff, that's just Catholics and Lutherans iirc.
The Anglican Church (The biggest Protestant Church in the world) has Bishops and Arch-Bishops and it's head is the Queen of England.
Christian Cults have religious leaders, and hierarchies towards them, as do many sects.
Furthermore you get unofficial leaders, who act as preachers and command great deals of respect among their followers, solely because they preach their religion.
This is true not only in Christianity but many religions.
Muslims have Mosque leaders.
Jews have Rabbi's who lead their Synagogues.
Buddhist Temples have high Monks. Tibetan Buddhism has the Dalai Lama.
In Tribal culture there are Shaman's and Wise Women who lead the tribes.
Every religion has some leader. Whether they're an important historic figure, a member of the religion who guides others in the religion, a high-priest who claims appointment by God, or even God itself.
Jesus and Buddha also existed. The people just follow some of the things that they taught. Kind of like atheists follow some of the things that have been taught by many different people.
I guess you could say religious people follow one or few leaders while atheists follow many different leaders who are usually unrecognized (authors, philosophers, whoever else they follow).
This is also incorrect.
Atheists do not follow anyone.
Just because someone writes atheist philosophy it doesn't make them a leader to all atheists. It doesn't make them a leader at all.
They don't have any jurisdiction over other atheists because they've written and shared their opinions.
Other Atheists (a massive minority) might quote certain atheist authors in order to back up their personal views, but this doesn't make that person their leader.
In the same way that Christians might quote certain religious philosophers and theologians, but those people aren't leaders to them. They don't do as they say.
They solely use what they have said as a way to explain their views, because explaining such fundamental and philosophcial views is difficult. And if someone has said what you believe in a clear and understandable way, then you might as well repeat them, because it's easier than fumbling around trying to explain your view by yourself, where you might make mistakes and confuse people.
Atheists, as a whole do not follow people.
Generally as a whole, theists don't even have to follow people. Religions however do.
Atheism is just the act of not believing in a deity (or theist God).
You are getting Atheism confused with the sub-culture of people that are also Atheists, but are also usually anti-theists, and make it a goal of theirs to spread atheistic views. These people do look up to certain philosophers and scientists and authors as leaders. But that doesn't make those people the leaders of Atheism or Atheists as a whole.
The large majority of Atheists do not think about being Atheist.
In the same way, the large majority of theists do not think about being theist.
It is just a view you have, which sits in the back of your mind. It might mean you follow certain practises, or enjoy certain things, but it's not the guiding thought in the mind of every person.
People who do have it as their guiding thought and do everything single thing by it are the minority.
And it is because of those people that religious people get their image tarnished, as people assume they are extremists, and so too do atheists, as people (like yourself) assume they all live, breath and sleep atheism.
You are not allowed to call yourself an atheist is you believe in a deity, thus making it a requirement, which also makes it a group. If you believe in a deity or supreme form, you have to call yourself religious.
No, that's completely wrong.
I understand what you're getting at, but just because there is a "requirement" doesn't make it a group.
It's also not a requirement, but a characteristic of Atheists.
In the same way that I am White because I have White skin. To be White you have to have white skin, but that's a characteristic. You wouldn't call it a requirement, because it's not a group you join. You're either White, or you're not.
The only difference here is that you can change from a theist to an atheist. But nothing changes about you when you do that other than your opinion of the world. There aren't any rallies, or exams or entrance requirements. No one organises entry. People don't even have to know you're now an atheist.