Most of the stuff on that site is stupid.

However, the part that you've extracted is largely correct. Proofs that god exists or doesn't are not scientific, they are philosophical.

OTOH, the fact that many scientists of the past believed in god is not particularly relevant. Most of them were brainwashed deeply by their societies from a very young age.

Einstein's religiosity was indistinguishable from atheism. The same could be true of other erstwhile religious scientists.

Belief in god seems silly to me. That's not a scientific view. It's a philosophical view.