At our Seder, one of the non-observant guests asked if one could invite non-Jews to the Seder. How does one answer such a question without giviing the impression that orthodoxy is intolerant? Chag Kasher v’Sameach
Without going into detail explain that inviting a gentile to on a festival involves overcoming technically many halachic difficulties (you can mention that the laws forbidding cooking apply on festivals as they do on Shabbat with only few exceptions) and this makes it almost impossible for the average family. Point out that when diplomatic protocol requires it, Israeli embassies have been able to have gentile guests and have overcome the obstacles halachically (see Mishna Berura 512 6).