From the article, explaining why they think it's an "Atheists Worst Nightmare":

Garland’s writing frequently reaches for this sort of inverse Spielberg effect, where secular revelation is inseparable from existential horror. Much like his later works Ex Machina (2014) and Annihilation (2018), which also combined highbrow philosophy with good old-fashioned schlock, Sunshine plays out as an atheist’s worst nightmare. Imagine: you’ve staked your life on rational science and journeyed into the very gut of the galaxy, only to discover something irrefutably Godlike, terrifying, awe-inspiring and utterly impartial towards your continued existence. Perhaps those sun-deifying ancient civilisations were right all along. The sun giveth and it taketh away, and if it decides our number is up, who are we mere mortals to argue?

That's not even remotely an "atheist's worst nightmare." A deity exists and it's horrifying? That's a theist's worst nightmare, and the basis for several arguments for atheism.

Oooh Ray Comfort's banana has nothing on this.

Edit: Also, "into the very gut of the galaxy", for fuck's sake, THE FUCKING SUN is not the gut of the galaxy.

From the headline I would've thought this was Screenrant. Did I miss when the Guardian started using the cheapest of click-bait?

Also, good movie, except for the ending - it is Alex Garland after all.

basically Project Hail Mary’s older, emo cousin

Yeah, straight from the start, there's signs that this author is trying so hard to be smart and failing miserably.

How could the existence of a god be the basis for an argument for Atheism? Atheism conceptually requires that no god exists.

That being said the headline is dumb because from what I can gather the premise of the movie is that god is real but it’s not the one that anyone in the modern world is worshipping, so it would be equal in nightmare across theists and atheists alike

Me an atheist reading cosmic horror since 1999 "ooooooh evil outer gods scawwy"

It works like this:

1. Assume for the sake of argument that the deity exists.
2. Examine the horrific, implausible, and logically absurd implications of that existence.
3. Use those as evidence that the deity doesn't actually exist.

One of my favourite movies

As an atheist, no it doesn’t

The argument goes something like this:

"I refuse to prove that I exist," says God, "for proof denies faith, and without faith I am nothing."

"But," says Man, "the Babel fish is a dead giveaway, isn't it? It could not have evolved by chance. It proves that You exist, and so therefore, by Your own arguments, You don't. QED."

"Oh dear," says God, "I hadn't thought of that," and promptly vanishes in a puff of logic.

"Oh, that was easy," says Man, and for an encore goes on to prove that black is white and gets himself killed on the next zebra crossing.

Ah, I see you're a frood who really knows where his towel is.