“How can a loving God allow [fill in the blank]?”
There may be questions Christians are more likely to hear from unbelievers than the various permutations of the above, but I can’t think of one at the moment. The query may be a defiant attack on the character of God or the honest expression of perplexity by a genuine seeker. Either way, the answers that satisfy you or me rarely settle the matter for those who do not know Christ.