It just means people are upset when they see something new.

Some people are upset by the change for other reasons.

"I can see how that sort of thing would upset people."

"Maybe people are upset we bought a picture for such a good price."

Yes, I know, some people will be upset by my proposed changes.

At the news of the pregnancy, several people in the house were upset.

"Most people are upset by this and sorry to see it," said one person close to the family.

"I think people were upset that it was put back up for a vote," she said.

Many people were upset by this idea, it was quickly dropped.

I think people get upset just because it's called a "kill bit."