Kvia'at seudah

Question

Dear Rabbi, I noticed you previously replied that "Items eaten as a bread are hamotzie, including bagels, rolls, pizza, and Matzah. " Recently in our Kniss there was a seudat misvah and they brought in "mezzonot" challah ( I guess with fruit juice or the like). However people stuffed their plates with salads, meat/chicken, rice potatoes etc along with this "mezzonot" bread. In short a whole meal. The Rabbi ( A Sephardi) ruled to say mezzonot and I had few words with him but did not want to make a scene ... Question: (after the fact) should the congregants have blessed "Hamossi" or Mezzonot? 10x 4 a prompt reply and there is another seudah scheduled soon..