It's just because they are thoughtless generally.

It doesn't do to listen." "No one ever said anything unkind about you," he said.
"Oh, didn't they ?" Juliet smiled.

"Do you know, Robin, I shouldn't wonder if there are plenty of them saying unkind things about me this very moment--that is, if they are thinking about me at all." He glanced around him savagely.

"Where?
I'd like to hear 'em! I'd kill 'em!" "No--no!" said Juliet, restraining him.

"And it's no one here either.