Something that's innocuous isn't harmful or likely to cause injury. Public figures like mayors and governors have to expect they'll get critical or even hurtful emails and phone calls, as well as more innocuous feedback.
The adjective innocuous is useful when you're talking about something that doesn't offend or injure anyone. Innocuous remarks or comments are meant kindly, and innocuous germs won't make you sick. An innocuous question is innocently curious, rather than aimed to hurt someone's feelings. The word comes from the Latin roots in-, "not," and nocere, "to injure or harm."