Intent is the difference between manslaughter and murder. It's the difference between a clerical error and fraud. It's the difference between unauthorized entry and buglary. Courts consider intent every day, and consider it when arriving at appropriate punishment.
The thing about Hate Crimes legislation is that it deals with the motivation behind the intent, which is taking it a step further.
As an example, suppose I ran over somebody with my car. If it was an accident, I might be reckless or negligent or drunk or something. If I did it on purpose, I am guilty of homicide. If I did it because of the person's protected status as a minority, then I would be guilty of some additional hate crime.
This is this case if they called it in you would consider it intent, and if they didn't they should just be guilty of posting signs without a permit.