Why not Angel Gabriel directly come to people| Atheist Question and My Answer

In Atheism the most fundamental problem is that they want to see evidence according to their own wish. In this regard Atheist's one of the most repeatedly asked questions is Why Angel Gabriel or Jibreel or Jibrail come to messangers like Mohammad PBUH and Jesus Christ PBUH and Why not God sent Angel Gabriel or Jibreel or Jibrail directly to the people so everyone know the reality of God. As Atheism is defined as a rational approach So I have answered Atheis's question logically not by the scriptures.