This is Frequently Asked Question/Frequently Offered Claim. It seems to stem from the Atheist requirement for less subjective evidence of God.
Atheists have a more empirical criterion than Christians do. Generally an Atheist will not settle for any testimonial or subjective evidence while a Christian will. Since Atheists are not likely to accept anecdotal or subjective evidence for God, they prefer the kind of evidence that results from something like but not limited to a scientific style inquiry.
When faced with a conclusion that does not seem to follow from the evidence, isn't it normal to want more evidence which better supports the conclusion? Law, Law Enforcement, Medicine and Science are only a few fields that depend on having a conclusion as qualified as possible, as certain as possible. Arresting a person, sentencing a person to prison, performing surgery and showing results from scientific grants are actions that depend on a conclusion based on sound evidence. It just won't do to settle for "maybe". Since the prospect of a God has the potential to influence every part of our existence it follows that we should as sure as possible that God exists.
So if the Atheist is not convinced by the evidence presented, it should be expected that the Atheist would want more evidence. This evidence could be as dramatic as imaginable or it could be as subtle as something personal. If God is everything he is supposed to be he knows what it would take to convince us. If God wants a relationship with us, then he should be as present as necessary to create it and sustain it. Christians claim that he does and that Atheists refuse it. But I think a strong argument can be made that an all powerful being could, with a minimal amount of effort, be undeniable if it wanted to be.
What are our expectations for relationships with our friends, family, spouses, business acquaintances or strangers? What does it take to sustain those relationships? Most of the time, its not tricks, just a little understandable feedback.