In Matthew 2 we see the story of the Magi coming to visit Jesus. As they looked for the newborn king, they went to the capital, Jerusalem. When Herod the Great heard about this inquiry, he was troubled, Matthew tells us. I guess so. If a new king was born, the current king would certainly expect to know about it.
But Matthew notes that "all Jerusalem" was also troubled. I have always thought that the citizens were worried about King Herod's reaction to the news. But maybe these citizens were worried about the possibility of a new king upsetting the status quo.
In any society there are people who want to keep things as they are. They want to conserve the current systems. If the system works for me, why would I want it to change? Sure there are people who are struggling, but they can thrive too if they will get with the program.
But when this newborn king grew up, he turned things upside down, declaring that the poor in spirit, the mourners, the meek -- these were the blessed people. This message would really challenge the status quo.
So, yeah, Herod and the powerful people in Jerusalem were right to be troubled.