There is a lot of that entitlement to go around in other states with other schools. Around here, it is KU over KSU. It is tiring to always have people thinking they are superior because of their affiliation with one school rather than the other but usually the really rude/destructive/combative types are few and far between. One friend described it as people being surprised that she is a KSU fan when she could be a KU fan. Definitely an annoying attitude. Since there are so few unc fans around here, there is generally an exchange of good natured ribbing. I did replace someone's tar heel shirt with a beautiful Duke shirt. I was going to use the tar heel shirt to wash my car but I'm afraid it will hurt the paint.
A piece of mail delivered to your house from a much disliked sender shouldn't be such a cause for distress - especially if it is addressed to someone else. One possible solution - if they include a business reply return envelope, put all the paperwork they sent, including the envelope, and send it back with a request to be removed from the mailing list. They pay for the privilege of getting their mailing back. Please note: This should only be done by the addressee and not a spouse.