I'm not sure I understand what you mean. Are you saying that an ambassador cannot speak on a subject which has nothing to do with foreign relations or his assigned country, even when he is sitting at home in the US, in case that might offend some people in the country he is going to?
A large population of Israel is Arab. Should the American ambassador to Israel forego any condemnation of Arabs or Palestinians, even while in the US, for fear of offending that ethnic minority?
Certainly while serving, an ambassador should avoid an prsonal controversies whenever possible.
You are making a generic case, I am discussing a specific one. To support the homosexual agenda is destructive, even when at home. That was my only point.
Shalom.