Why not? Because we have an abundance of empirical evidence that all of these things are real. People have experienced them first hand, can observe them and interact directly with them. There is no need to ‘prove’ or argue for their existence.
There are, however, hundreds of sites – plus books and broadcasts – that argue for the existence of God. This is telling. It is, whether those offering such arguments realise it or not, a blatant admission that there is no empirical evidence for him. If there were, there would be no need for argument and ‘proofs’; no need for apologists to resort to persuasion that is ultimately self-refuting to ‘demonstrate’ his existence. No need for apologists. Their problem is, of course, no-one has ever met God nor observed or interacted directly with him. Not in the same way people have met President Obama, seen him on the television, heard him speak or interacted with him in person. No-one has done anything of the kind with God, not even those who claim they have and feel compelled to tell us all about it. Every encounter with the Almighty has taken place in the mind of the individual experiencing it, just as St Paul admitted. God himself has never made an appearance.
So, yes, it’s very telling, this having to argue for God. If there was clear evidence of him there wouldn’t be any need to devise arguments for his existence; he’s not, or shouldn’t be, a philosophical proposition. An omnipotent, omniscient, omnipresent, creative being would, by dint of his immanence (presence in this world), be somewhat obvious and there would be incontrovertible evidence of his existence. Christians and other god-botherers say there is such proof, citing Nature, Goldilocks universes, Holy Books and personal experience. But these are far from incontrovertible, being much better explained by other means, none of which involve God. His very superfluousness demands that, through the application of Occam’s razor, he be discarded; not, as apologists would have it, rebranded as ‘transcendent’, a sleight of hand allowing them to proffer unreality as the ultimate reality.
The desperation to convince others there’s a God with an existence outside the human imagination is, then, more than adequate demonstration that there isn’t. Christians and others who want us to believe their God is real, protest much too much and in so doing, demonstrate precisely the opposite.