After feeding the five thousand in John 6, why did Jesus withdraw to a mountain alone?

Answer: They meant to make Him king by force

The people called Him the Prophet, and Jesus, realizing they would make Him king by force, withdrew to a mountain.

“When the people saw the sign that Jesus had performed, they began to say, “Truly this is the Prophet who is to come into the world.” Then Jesus, realizing that they were about to come and make Him king by force, withdrew again to a mountain by Himself.”— John 6:14-15 (BSB)