Virtually everyone has been on the receiving end of this statement: "I was offended because you--"
You can fill in the blank. "You made the sign of the cross." Or: "You have communion every Sunday." Or: "You chanted the introit."
Whatever it is, the question is how to deal with those offended by things that are either just part of catholic Christianity (such as chanting the introit) or are a part of being a confessing Lutheran (such as the sign of the cross, or the Mass).
The "offence" doesn't go the other way. Or at least it's usually not said out loud. No one says, "I'm offended that the congregation doesn't sign themselves with the cross." No one grumbles, "I'm offended that you only celebrate Holy Communion twice a month." No one mutters, "I'm offended that you don't use incense with your prayers."
I wish I could be more sympathetic with the offended. I used to be. I used to listen more patiently, hearing silently the endless tales of their offense.
I'm not very sympathetic now. When folks complain, I usually think, not unkindly, "Then go somewhere else." If you are offended because our Mass [another "cause of offense" to some, but that's another issue] seeks to be what the Mass has been throughout the Church, then I don't know what to tell you, except that it's not going to change, and that maybe you are offended because you are weak. (See Romans 14). And if you are weak, it is my job to be kind to you, to pray for you, and to instruct you. But it is not the job of the church to change because of how weak and erring brethren feel.