This is pure autobiography...
IF the argument is about the reality of a deity - arguments such as the Five Ways of Aquinas, for example - then it is rejected because obviously such simple 'proofs' cannot prove the reality of something as complex and many-faceted as the Christian God.
And obviously simple arguments could not prove the reality of any kind of god which might have some personal relevance.
So such arguments are not engaged with, or perhaps held at arms length and studied academically - so that whether they are right or wrong becomes a matter of at most mild interest.
YET if the kind of multi-stage argument that might prove the plausibility and reality of something-like the complexity and relevance of the Christian God - an argument which would necessarily combine metaphysics, logic, history, psychology... all sort of things - then the atheist reacts with Woah there buddy! - One thing at a time! You seems to be assuming an awful lot of stuff.
So, anything short and simple is obviously too short and simple; anything more complex is too long, and too speculative.
It's a combination of what purports to be hard-nosed skepticism with a short attention span honed on the sound bite.
There is already a word for this: sophomoric - the wise fool. Wise in his skepticism, foolish in his impatience - productive of armour-plated arrogance.
And this is applied to the fundamentals of life, to the most important questions a man can ask himself...