The reason why we say that is because we do not put ourselves at
the level of God. To do so is foolish, because we cannot see things
from His way. He is on a much higher level than us, in the way that
fishes cannot comprehend what we are telling them.
And this part:
why would god still be god no matter whether we
understand or not.
what is the meaning of this sentence that you have made?
Is it like saying. A chair is a chair? What is the significance of
such statment?
This is an insult to your intelligence. Rhetorical questions get
you nowhere. What he means is, even if you could or could not
understand God, He still exists. Just like if I can't understand
the theory of Relativity, it doesn't disappear or anything.