Why people ask it
Because if the stakes are as high as Christianity says, ambiguity looks either careless or cruel.
Short answer
It is a serious objection. The Christian response is that overwhelming evidence would compel assent without producing trust, and that the kind of relationship being offered requires something other than coercion.
Deeper answer
This is one of the strongest objections and it deserves to be treated that way rather than brushed aside. Divine hiddenness has generated a substantial philosophical literature precisely because it is not easily dismissed.
The main response distinguishes belief-that from trust-in. A sufficiently overwhelming demonstration would produce belief the way a proof produces agreement — but it would not produce the kind of voluntary trust Christianity describes as the point. There is a difference between conceding a fact and giving yourself to someone.
A second response is that the evidence is not actually absent, just not coercive: the existence of a contingent universe, fine-tuning, moral obligation, consciousness, and a specific historical claim. Enough to follow if you are willing, not so much that unwillingness becomes impossible.
Common mistake
Saying "He has made Himself obvious, you are just refusing to see." That converts an honest question into an accusation.
Conversation-ready response
""That is a genuinely strong objection and I am not going to pretend it is easy. The best answer I have is that overwhelming proof would produce agreement, not trust — and trust is what is actually being offered.""
Source notes coming soon.