For what human reason was Christ crucified?
Luke 22:2 And the chief priests and scribes sought how they might
kill him; for they feared the people.
Essentially you have a ruling class of Jews who hated Jesus for political reasons. They saw him as rising in popularity and subsequently their own social and political positions were threatened.
They brought false accusations against him to the Romans as they were not legally allowed to put anyone to death.
Matthew 26:59 Now the chief priests, and elders, and all the council,
sought false witness against Jesus, to put him to death;
They thought they had the perfect charge to use against Jesus with what they saw as blasphemy.
Matthew 26:65 Then the high priest rent his clothes, saying, He hath
spoken blasphemy; what further need have we of witnesses? behold, now
ye have heard his blasphemy.
They were politically astute enough to recognize that the Roman administrator would not consider blasphemy a serious offense so they sought to present Jesus to Pilate as a promoter of sedition and rebellion.
Luke 23:2 And they began to accuse him, saying, We found this fellow
perverting the nation, and forbidding to give tribute to Caesar,
saying that he himself is Christ a King.
Pilate was not so easily misled.
Matthew 27:18 For he knew that for envy they had delivered him.
Pilate had himself been twice before forced to back down from a ruling he had made by the appeal of the Jewish leaders to Caesar. As a result, he understood the limits of what he could do. He attempted to get out of the corner the Jews had backed him into.
Matthew 27:21-22 The governor answered and said unto them, Whether of
the twain will ye that I release unto you? They said, Barabbas.
Pilate saith unto them, What shall I do then with Jesus which is
called Christ? They all say unto him, Let him be crucified.
Pilate calculated that he did not have the political capital to force his will against the Jewish leaders who had twice before got him in trouble with his boss.
What human reasons? Envy, hatred, mob mentality, and cowardice.