Why did Jesus' birth and resurrection happen so secretly or were revealed only to a few?

The scriptural evidence argues otherwise.
1. The birth of Jesus was announced by angels to the shepherds who not only visited Him but also talked about their experiences.
2. Before His birth there was the pre-evidence of Zacharias, Elizabeth, and Mary herself from her experience and visit to Elizabeth.
3. The Magi declared their finding to Herod who cross-referenced it with the Jewish scriptures, but tried to eliminate Jesus.
4. His birth was not a secret. Yet it was a mystery of Godliness against the mystery of ungodliness that is also at work in the world.

Resurrection
This was also no secret.
1. The guards knew about the supernatural visitation, the great angel who rolled the stone....
2. The priests also knew about it and tried to protect the guards by fabricating a tale of disciples stealing Jesus' body, which they were not able to prove and neither their persecuting the disciples could force them to change their testimony of what they saw. 
3. Obviously, given #2, the transformation of the disciples from timid to courageous witnesses was not the result of a mere visionary or subjective experience. 
4. There was claim of a larger body of over 500 people who saw Jesus post-resurrection. It wasn't hallucination. It was also not spiritism. Jesus ate with the disciples and Thomas touched His side.
5. Both Jews and non-Jews were aware of this and it was a stumbling block to both.

Does Evolution have a mind of its own? Does it decide?

Ever since Darwin, there is a tendency to ground human behavior (regardless of the ethical question) on some numinous mind or intent of evolution itself. One of the most popular is the gene or species survival argument that tries to explain several acts like adultery/promiscuity and even murder and suicide as grounded in evolution's intent to make more gene copies or ensure species survival, thus attempting to deterministically ground human behaviors in some underlying, unconscious (collective) force, principle or "archetype". Thus, the responsibility is shifted from the individual to the species and from the species to the "one" that created or made possible this species. This "one" is the new scientific reality, life, elan vital, God. The evolutionary psychologist Carl Jung went to the extent of believing Satan (or the archetype of evil) as the fourth in the "divine quaternity", for he thought the Trinity was insufficient. Genesis 3 gets repeated. What elaborate enterprise to self-deception!!!!!