Nobody is suggesting that Pilate was the only one?
How about millions of biblically-inept churchgoers who recite this week after week:
"..His only Son Our Lord, Who was conceived by the Holy Spirit, born of the Virgin Mary, suffered under Pontius Pilate,..."
No one else is mentioned.
And the effort Pilate made to free Jesus was not just a small effort, for he argued with them for hours and even tried to compare Jesus with Barabbas so they would obviously free Jesus instead:
Luk 23:20-22 NLT - 20 Pilate argued with them, because he wanted to release Jesus. 21 But they kept shouting, "Crucify him! Crucify him!" 22 FOR THE THIRD TIME he demanded, "Why? What crime has he committed? I have found no reason to sentence him to death. So I will have him flogged, and then I will release him."
Pilates argument with the ppl of Israel is akin to a politician yelling at his voters to convince them of his opinion—no easy task, and it doesnt happen like that nowadays. Politicians rally with their own echo-chambers and rarely, if ever, face off against public opposition.
***
And the passages you cited dont disprove anything, since the Apostles know very well what being flogged was, yet they still attribute the suffering of Christ to the ppl of Israel, and so did Christ himself. .
Why would the Jewish leaders want to kill Christ? Well, the bible isnt a big set of books, so theres no reason why everyone doesnt know this already:
Jhn 11:47-48, 53 NKJV - 47 Then the chief priests and the Pharisees gathered a council and said, "What shall we do? For this Man works many signs. 48 "If we let Him alone like this, everyone will believe in Him, AND THE ROMANS WILL COME AND TAKE AWAY OUR PLACE AND NATION" ... 53 Then, from that day on, they plotted to put Him to death."
Cant be much clearer, and for you to ignore the words of the Apostles' actual biblical words bespeaks of a cultic belief in a manmade mantra, rather than a biblical belief in the inspired Word.