The Mass is the name for the Eucharistic Liturgy of the Latin Rite. The name for the Eucharistic Liturgy of the Byzantine Rite is The Divine Liturgy. Some people tend to be sticklers for proper terminology and Divine Liturgy is not called the Mass. It is definitely a latinization to do so. It seems to be more of an issue with Byzantines. I know a number of Maronites and Chaldeans who refer to their Eucharistic liturgy as a Mass, even though it is actually Holy Qurbobo. I wonder if it is a linguistic thing . Perhaps, when learning English, they were told that the English word for Holy Quobano is Mass. I even know a few Orthodox who call will occasionally say that they went to Mass. You are certainly well understood if you say Mass. Those who correct you are just trying to teach you the proper terminology. Sometimes, they can be a little obnoxious about it.