While Paul Newman is alive it is relatively easy to prove that I met Paul Newman. All we have to do is ask Paul Newman. Proof is easy.
However, you cannot assess others' experiential evidence.
You are correct, but without evidence to support their experiental evidence it can be dismissed without evidence. Would you believe me if I told you that I had a pink Unicorn that talks to me?
Of course it can be dismissed...by those who don't share such subjective evidence. Other people's subjective evidence is pointless and useless to you and I.
However, getting back to the point, based on such experience or its lack, one can be certain that God exists, or one can be uncertain; it's impossible to be certain that God does not exist based on your personal experience. Within this narrow frame, that leaves one an agnostic (one who lacks knowledge) rather than an atheist (one who is certain that God is nonexistent).
No. Only the blue ones talk.
You heretics who claim pink ones talk can't prove anything!
;-)