Do you agree w/ this sayin......??

I can look at it one of two ways. One way, if there were no God, people would still choose to have a deity and there would still be those who chose to disbelieve in a deity. But on the other note, if there were no God, then perhaps we wouldn't have the desire to worship a deity, so all would be nonbelievers which would render the term atheist unnecessary since there would be no distinction.

In a way you are right. If no one believed in a "God" then we would all be atheists. Since there would be no need for the distinction then that title would no longer exist.

I'm not sure I understand. is this trying to prove the existance of God because people don't believe in him/her/it? if so, does that mean that Unicorns exist? sure, if there was no concept of the possible existance of deities, then there wouldn't be a name for people that believe no deities exist. but the fact that there are atheists doesn't prove the existance of any particular Gods.

Absolutely, I agree with that 100%. If there wasn't a God, there'd be nothing to not believe in, right?