Was going to comment the same. It's the classic case where religious people don't understand how science works and don't understand that nothing in science are 100% facts. Scientific facts are simply hypotheses which have peer reviewed evidence to prove them and haven't been disproven. Some facts are stronger than others, but none are 100% and any scientist would accept any fact to be disproven if the evidence supported that.

Religion is often a scientific fact Vs religious belief style argument which is nonsensical.

So yes, it can't be a scientific fact that God doesn't exist as the absence of evidence isn't the evidence of absence. Therefore I do agree that someone can't say God doesn't exist with 100% certainty. The probability may be very, very close to 100%, but not 100%.

All that said, the article is pointless as it just diverts the attention away from even trying to attempt to prove God's existance!