Likely because they know it is a symbol for you, NOT the Real Presence as it is in the Catholic Church. Since you have no desire to accept Catholic teachings, and,I assume, don't believe that in Holy Communion in the Catholic Church, you are taking into your body the Body, Blood, Soul and Divinity of Jesus, why would you be offended that you are not included? It's not just a 'feel good' thing for us.
SuziQ,
Holy Communion is not just a feel good thing for Lutherans either. We believe, as our Lord states, that the bread and wine in the Lord’s Supper are His true Body and Blood. This is why orthodox Lutheran’s practice closed communion.