I expect that this has a great deal to do with the fact that the findings of modern cosmology has supported the idea that the universe began to exist, whereas the notion that anything which begins to exist has a cause is a metaphysical principle – which many atheists feel free to reject.
However, it is the first premise that any real supporter of science will defend most strongly. Claiming that things can come into existence without a cause is to cease to think scientifically and resort to magic.
That is, the whole of modern science is a search for the causes of things. It is founded on the idea, then, that events have causes. Anyone who simply rejects this notion can hardly be said to have a “scientific mind”, and to suggest that things can come into existence without causes is positively anti-science.
To dismiss this idea strikes me as one more attempt to give a simple answer to a complex question. Simply concluding “the universe doesn’t have an explanation, it just is” is surely as much a halt to inquiry as anything the most fundamentalist preacher has said. That being the case, it seems that there’s absolutely no reason at all too think this – and good reason to reject such statements as anti-intellectual.
If someone is willing to dismiss a pillar of western philosophy that also happens to be the intellectual basis of science in order to avoid the conclusion of an argument, well, it is hard not to conclude that the discussion has left rationality behind. Personally, I find it very difficult to picture someone seriously saying that he doesn’t believe in God because he thinks things can come into existence without a cause.
Certainly, anyone who takes this tact is abdicating all claim to defending science.