Rofl. What I tend to encounter is a lot of a-theists who don't know the history of two words.

16th century: There was no word "theist" in existence, to attach an "a" prefix to. Christians pulled the word "atheos", in full, from ancient Greek, and added ist/ism suffixes to it. Atheos + ist = someone who believes no god exists.

17th century: The same was done with the word "theos". Theos + ist = someone who believes a god exists.

18th century: You'll find D'Holbach having no label for those he calls undecided, not calling them "atheists". You'll find his opponents, representing the common usage Christian majority, clearly using the athe-ist definition. Their problem though, that they clearly laid out, is that they used faulty logic, claiming not believing gods exist = believing gods do not exist. So, while using the athe-ist definition, they were labeling all non-theists with it.

19th century: Huxley came along and, while acknowledging he was someone they'd label "atheist", argued he didn't actually hold the belief attached to the label, and wasn't particularly fond of those who did, because he thought they were distorting science, his favourite thing. Being a scientist, above all else, he defined agnosticism as a form of demarcation. No objective testable evidence = a subjective unfalsifiable claim. Results: unscientific and inconclusive. No belief as to the truth, or falsehood, of the claim. Incompatible with theism. Incompatible with athe-ism.

"Agnosticism is of the essence of science, whether ancient or modern. It simply means that a man shall not say he knows or believes that which he has no scientific grounds for professing to know or believe." ~ Thomas Huxley, 1884

X = a god exists

Objectively: X or ~X

Subjectively:

Do you believe X?
Do you believe ~X?

YN: the(os)-ist
NN: agnost(os)-ic
NY: athe(os)-ist

20th century: then came the likes of George H Smith and Antony Flew, who promoted a broader a-theist definition. They fully acknowledged they were promoting something new, or uncommon, and fully acknowledged they were hijacking the agnostic position into "atheism".

"In this interpretation an atheist becomes: not someone who positively asserts the non-existence of God; but someone who is simply not a theist. Let us, for future ready reference, introduce the labels ‘positive atheist’ for the former and ‘negative atheist’ for the latter.

The introduction of this new interpretation of the word ‘atheism’ may appear to be a piece of perverse Humpty-Dumptyism, going arbitrarily against established common usage. ‘Whyever’, it could be asked, ‘don’t you make it not the presumption of atheism but the presumption of agnosticism?’" ~ Antony Flew, 1984

Using their definition ...

YN: the(os)-ist
NN: weak or negative a-theist
NY: strong or positive a-theist

21st century: Online a-theists promote the same word reconstruction for "agnosticism", turning agnost-ic into a-gnostic, not a gnostic, making it compatible with beliefs, and including gnostic positions.

Do you believe X?
Do you believe ~X?
Do you "know" X?
Do you "know" ~X?

YNYN: theognostic (or gnostic theist)
YNNN: theist (or a-gnostic theist)
NNNN: agnostic (or a-gnostic weak/negative a-theist)
NYNN: atheist (or a-gnostic strong/positive a-theist)
NYNY: atheognostic (or gnostic strong/positive a-theist)

And, no, that shouldn't be 4 positions. The 4 position models they're passing around are nonsensical false dilemmas, that pretend to offer all the options, but simply drop ask beliefs about ~X.

Do you believe X?
Do you "know" X?
Do you "know" ~X?

YYN: gnostic theist
YNN: a-gnostic theist
NNN: a-gnostic a-theist
NNY: gnostic a-theist

^That just mashes NNNN and NYNN into one.

Also, probabilities actually require evidence to work with, testing and retesting, crunching the numbers, to come up with a result. Flipping a coin over and over, and keeping track of the results, indicates a 50/50 probability. With an objective truth question it's either 100% true, or 100% false. I just have no clue which. There's no a 50/50 chance it's going to go either way. At this moment, the most distant star from us in the universe has an odd or even number of planets orbiting it. 100% one or the other. There's no 50/50 chance it's either. I just have zero clue which it is. There's a 50/50 chance your guess is right, if you make a guess. I'm not guessing.

If more people like to Believe / Interpret the word "Agnostic" as uncertain about a God 50 /50 then the word has got another synonym linked with it. We just Interpret our words for what they mean. With me anyway.