And logic does not equal truth.
This is very true, and sadly, most (all?) cults are created on the basis that sinful man believes that their sin-based "logic" is more reliable and dependable than God's word.
How can God be 3 yet 1 ?
How can Jesus be both man and God at the same time ?
How could Creation be ex nihilo ?
You have to remember your audience.
The poster you're responding to is a Mormon, and so he denies the Trinity, and believes tha the godhead is three gods, not just one.
He doesn't believe that "man" and "god" are different species, but the same species, God being an "exalted man". The best analogy I've come up with is man is the "caterpillar" form, God is the "butterfly" form.
Mormons reject ex nihilo, and believe the universe has always existed.
But in their own way, Mormonism is a great example of cults which exalt their own "logic" (in the claim of false "prophesies" from God) over God's word.