Your view is utopian. Not all atheists are caring, peaceful people. Some are sociopaths. Some are still racist or ethnocentric, some are ultra-nationalistic right wingers. Some believe in the culture of greed. Religion is, by far, not the only source of violence and conflict.

Have we learned nothing from Orwell's Animal Farm? Nothing would change but the names and titles.

People will always find a way to muck things up. Religion is just an accelerant for the fire of human stupidity. Saying that, I do think it would be much better. People who think for themselves make better choices and think more clearly.

Being atheists isn't some sort of "magic pill" that would make all of humanity
better than it is.
There will never be any kind of "Utopia". That is nothing more than a fantasy.
Humanity is incapable of creating such.

Would a discussion forum ruled by athiests be free of disagreements, competition and petty meanness?

Your theory has merit. I would love to see what the world be like without religion.

The only thing we really have in common is we do not believe in gods or a god. We still have differences; disagree and argue. Some will always take it too far or too personal. So no, nothing would change if atheists ruled the world

Only one thing makes an A-theist, a non-belief in god(s), other than that an A-theist can be anything or believe anything. It would take a Humanist to create a world as you describe. Some A-theists are humanists and some are not.

As long as their is still economics, there will still be poverty, and therefore crime and war.

No way. On world always will be violence and other stuff because we are just humans and humans always do wrong things, and on Earth are some peoples who knows better than others, but this is just my opinion

I see no reason tho think that, atheists are just a capable of terrible acts as anyone else, we just don't have an imaginary friend advocating them.

Most of the atheists I know are as ideologically bent as most of the Christians I know... only in opposite directions. Peace isn't about "god," it's about our ability to allow others to be who they want to be regardless of what we feel about that.

Well let's see what it looks like in secular societies: Iceland, Japan (technically atheist), France, Scandinavian countries: more gender equality, more social equality, less aggressiveness (war), more fair taxation.
Multiply that effect to all countries: more equality everywhere, rational and science based evidence laws and regulations, a real effort to global warming, lower carbon footprint, fair taxation.
seems more positive to me.

...

They are already running the world under the guise of religion, but are corrupt and power hungery.

No, greed has nothing to do with religion.
But from other aspects, it would be better. Many wars begun and still begin because of religion.

Your hypothetical is only if atheists "ruled the world" it does not say they rule a world where there is no religion. So long as religion exists, nothing changes, regardless of who is "ruling the world". Also, I don't think any system where one "class" is "ruling" the others, is a recipe for success. Where one group is in charge, maybe. But, ruling another individual, for me, implies taking away the choices of others, that you know best and are going to tell them how to live.

Even if we take it to a more acceptable system of atheists being in charge, and religion having gone extinct by natural means (with no coercion), I think we simply trade one set of problems for another. I don't believe that humans know how to live in peace, or just live as one gigantic tribe of humans. They will consistently look at ways to break into tribes...to find the differences as opposed to the similarities.

You see it on Facebook all the time. You can belong to a comic book group, and people will go to "war" over which is better, Marvel or DC. Then battle lines are drawn, assumptions are made about a whole group, people start to call each other names, and the group is torn to shreds...over something as silly as comics. They want to focus on their differences as opposed to being focused on their mutual love of comics. Why do you think we have sooooooo many sects of Christianity - all saying the other isn't the "true version"?

Humanity is too prone to tearing itself apart, than bringing itself together. So my view is that, like most ideals, Utopia is something for which we should strive, but we must realize we will never achieve it.

Not entirely convinced that Athiests would end all wars, poverty, famine etc still too much testosterone flowing around to cloud judgement and create friction where none is required.

However...

I would like to see what the world would be like if female Athiests ruled exclusively and executively making all legislative and governmental policy decisions. Now that would be interesting...????

We would hope so! Our arguments with one another would hopefully be held with logic and reasoning to come up with a solution but we never know!

Nope. Too many worship money. There would still be the me first and those with money and power would still rule as they do now. Inequality would remain
.
Wars would be fought over oil and resources, and not who has the most powerful imaginary friend, but they would still be fought.

My first thought is it wiuld probably be the same, but then I considered atheists are typically more progressive than average (thus we're atheist), so maybe things would be better.

Oddly enough, Communism which is conflated with atheism requires violent overthrow of an existing order as one of its stages. Perhaps, killing other humans is in the hearts of all ambitious persons and thus is part of the natural order of things.

USSR and now Russia are atheist.

Since atheists are smarter I think it would have to be a little better. I think things could improve for women particularly, since sexism is (in my opinion) much more connected to religion than the other "isms." Homophobia might also get better since laws against being gay would be repealed. Getting rid of theocracies would do wonders for human rights.