There are certain rules already governing harassment. What I am saying is that I do not want a different standard or level of culpability in the workplace. If your neighbor starts harassing you - there are legal means to address those and a standard of behavior in the legal real which needs to be met. There should be no difference in the standard on what constitutes harassment in the workplace. And, in my opinion the legislation surrounding workplace harassment - is much more broadly interpreted.
The kind of harassment one might get from a neighbor is not the same as on the job harassment. That's why the definitions of unlawful harassment are different for neighbors than they are for coworkers. And your neighbor isn't the one writing up your reviews or making your raise recommendations. You can ignore your neighbor or give him back a dose of his own medicine without worrying that he'll go into HR and announce that you're incompetent and so he's firing you. And you don't have to worry about your neighbor giving you an undeserved bad reference sometime in the future of your career.
Sometimes innocent intentions are interpreted incorrectly, and that really is a shame. But that's up to the accused to fight, and he or she should. But for every innocent intention there are many people who had to live with rude and cruel treatment in the workplace or face homelessness.
If someone feels the need to harass their subordinates by way of insulting their heritage, or touching them, propositioning them, calling them names, making them take up the slack for the employees that they like better...then they probably shouldn't be responsible for the productivity, morale and safety of others anyway.