Roger tells Robert that Jack is going to sharpen a stick at both ends and use it to hunt pigs.
He was going to beat Wilfred
Ralph does not tell Roger anything in chapter 10. Roberttold Roger that Jack was going to beat Wilfred. he told Roger that Jack had ordered Wilfred to be tied up and had then left him tied up for hours, waiting to be beaten.
Roger initially decides to go up the mountain with Jack and Ralph in "Lord of the Flies" because he is a member of Jack's tribe and follows his orders. However, Roger's true motivation for going up the mountain is to partake in the ritualistic hunt and violence that Jack promotes, satisfying his sadistic tendencies.
It seems to mean that Jack's presence was drawing out the evil in Roger.
Wilfred was the member of Jack's tribe who Jack ordered to be tied up, although Robert was unable to tell Roger what Wilfred's 'offense' had been. He was then left tied up for several hours before being beaten by Jack.
I think Roger ...
Ralph, Jack and Roger search the island and climb the mountain in their search for "the beast."
When Robert tells Roger that the chief had order the boys to tie Wilfred up Roger asked the same question, why? Robert didn't seem to know. All he could tell Roger was that Jack intended to beat Wilfred, had order him to be tied up and Wildred had been left tied up for hours.
In "The Lord of Flies", Roger begins to take on Jack's traits and reacts in the ways of his leader. Although he had always had a cordial relationship with Ralph, Jack's hatred of him eventually causes Roger to hate him as well and go along with the plot to kill him.
Jack has Wilfred tied to a tree before Roger beats him. Jack accuses Wilfred of being the reason for a failed hunt and allows Roger to vent his frustration on him.
I think because he feels Jack is and probably will be a better leader than him. He feels if he criticizes him, he will feel better and appear that way to everyone else. Making him look the better leader.
Roger and Maurice are the ones that attack Jack and Piggy because Jack wants Piggy's glasses.