Do we have a right to feel offended? (Poor wedding etiquette)?

My mom and other family members were informed by e-mail by the mother of the groom (a close cousin of my mom, they grew up together) that my mom's side of the family were not invited. My mom's cousin impersonated my aunt on the email and signed my aunt's name (which my aunt was unaware of) . We found out later that my mom's cousin invited her dad's side of the family. Nothing was ever done to offend my mom's cousin by anyone in our family, and we always had warm feelings towards them all. Even if my mom didn't get a wedding invitation she was more hurt by not getting a proper wedding announcement. We were all made to feel that we weren't good enough because money and success are very important to my mom's cousin. My mom and dad are very respectable people, my dad had a good career as an RCMP officer and has worked hard all his life. Would others find this kind of treatment offensive?