"But why is it MANY people have religious and/or spiritual experiences ...and the ones that can't run around saying there IS no GOD or no spiritual world or any such thing!!" Why is That ?"
I'm going to make the (very dangerous)assumption that you're asking the question in all sincerity, that it isn't a rhetorical question, "asked" in order to make a point on which your mind is already made up.
My answer - valid for me only - is:
I grant that many people have religious experiences that are real for them (I omit "spiritual" because I have spiritual experiences - they just don't have much to do with the teachings of any organized religion - they're more personal to me). The problem is, I have no way to check out other peoples' religious experiences, to find out whether they're truly in communication with a higher power, or simply hallucinating. I have no basis to make a judgment. So I don't make one. I simply let the question remain open until I have some empirical evidence.
I do not deny the existence of God, or the gods, or anyone else that anyone believes in in the absence of empirical evidence. Although since there are so many different beliefs, it follows logically that most of them must be wrong, whoever's right. I simply am not prepared to accept it on the basis of someone else's say-so.
FWIW, I consider an atheist to be just one more sort of religious person. He has definite convictions about something concerning which there isn't enough empirical evidence to justify them, just as a conventionally religious person does. But a conventionally religious person might be getting information from a direct mental connection to the divinity, that I can't share. I can't prove he isn't. An atheist can't make that claim.
Show me empirical evidence and I'll evaluate it and go from there. In the meantime, you have your religious experiences and I'll have what passes for mine. But don't try to impose your truth on me either by force or by sheer blather, without hard evidence, because you'll only bore me at best, or piss me off at worst.
But maybe that was more than you wanted to hear on a Sunday morning. If so, I apologize.