I like to think it's the general base case that someone who has personal experience with something has a better hold on opinions regarding that something. That is to say, someone who codes for a living has a better held opinion of what it's like to be a programmer than someone who has never coded in their life. Or someone who is a painter has a better foundation for opinions regarding their particular style of paintings than someone who has never picked up a paintbrush. Cooking, hiking, reading, gaming, so many different aspects of life experience follow this principle.
Why is it that this principle does not extend to opinions regarding life in other countries? If someone has direct experience with actual life in that country, then they have a better reasoned opinion on it than you. If you have never lived in that country, have never known someone from that country on a level surpassing acquaintanceship, and have never even visited that country then your opinion or idea of life in that country is worth less than nothing. It's completely fabricated, or it has been meticulously contructed for you by someone else. It's inherently flawed because it has no real claim of legitimacy.
What does tend to happen is that some people see this "closeness" to experience as a pollutant. For example, because I have lived in Russia, then I must necessarily be polluted with Russian propaganda about life in its country. Because you have never set foot in the country and have never known anyone from there, you remain clear-headed and rational about your opinion of a place you've never been to. Why is it like this? I don't know the answer, but its reality is an essential ingredient to the condition cholic xenophobism that many Americans suffer. The slightest thought of another country being a fine place to live brings them pain. I won't project on the deeper meanings surrounding the genesis of this condition.
My favorite case study around this issue is John Steinbeck's "A Russian Journal". Steinbeck was disillusioned with the constant relentlessly negative press about Russia and the Soviet Union. He was dismissive of the constant news stories and general sentiment of Americans that Russia wants war with America and wants to invade/bomb it. Traveling to Russia, Ukraine and Azerbaijan himself he talked to the people there. He talked to regular people, government clerical workers, and members of the Foreign Ministry. He got the real experience of life in Soviet Russia from the people who actually lived there. Not surprisingly, this left him with an attitude of life in that country that was discordant with the general one of many Americans who never entertained the idea of visiting there. And this attitude would eventually turn out to be an "Anti-American" one when the second Red Scare decided to submerge our press with propanda.
This concept of personal experience debt is counter to nature's reason. Assuming intimate knowledge of something blinds you to the true nature of that something is inane. There is no way to learn about something other than intent study and reflection. Claiming that you know something better than someone else because you've spent less time thinking about or living it is one of the stupidest beliefs you can hold.