Exactly which country is "their own country" that all these people inhabited?
Assuming that there were "countries" defined the same way we define them today doesn't make historical sense.
But, even if we assumed that this miracle occurred in a place with clearly defined national borders, how can you be sure absolutely certain that no one in that crowd had citizenship outside the region they found themselves in that miraculous day.
The miracle of the loaves and fishes is recorded in all four gospel accounts in some form.
In the Gospel according to Matthew, it occurs directly after the healing of the Canaanite woman’s (also known as the “Syrophoenician” woman’s) daughter around Tyre and Sidon, and the curing of many others near the Sea of Galilee. When Jesus calls his disciples to him, he notes that he has compassion for the crowd “because they have been with me now for three days and have nothing to eat; and I do not want to send them away hungry, for they might faint on the way” (Matt. 15:32). So, we can safely assume that some of them were a long way from home. To simplify things a bit: he had a growing crowd following him, and he had been traveling around the region.
Also, how do we know that the Canaanite woman or her daughter didn’t follow Jesus after the healing, and thereby become a beneficiary in the loaves/fishes miracle? The Syropheonician/Canaanite woman is herself is a citizenship paradox. According to one Bible encyclopedia:
The woman from the borders of Tyre and Sidon whose daughter Jesus healed is described as "a Greek, a Syrophoenician by race" (Mark 7:26), and again as "a Canaanitish woman" (Matthew 15:22). This seems to mean that she was of Canaanite descent, a native of the Phoenician seaboard, Greek in religion, and probably also in speech. The names Syria and Phoenicia are both applied to the same region in Acts 21:2,3. Syrophoenician may therefore denote simply an inhabitant of these parts. According to Strabo (xvii.3), this district was called Syrophoenicia to distinguish it from the North African Lybophoenicia.
[Source: https://www.biblestudytools.com/dictionary/syrophoenician/]
In other words, exactly what country would claim her as a citizen? And how would she identify herself? My guess is that most Jews would see her as a non-citizen of the Jewish nation (even though her ancestors lived in Judea prior to the Jews) and most Romans would simply see her as one of many local peasants in a Roman province… but a Roman citizen? Who knows.
For that matter, the Jews themselves probably identified themselves as a nation more by their ethnicity (for obvious reasons, given their out-of-Egypt and Babylonian-exile migrations) than by their current place of residence. And, I doubt most Jews were Roman citizens.
But, for Romans (like the centurion Cornelius who came to believe in Jesus later, and the centurion whose servant Jesus had healed earlier in the same gospel account), Judea and Syria were simply provinces of the Roman empire. It was not a “country” belonging to its inhabitants. It was part of the Empire, and its true citizens were Roman citizens. The rest were peasants who owed taxes, but not true citizens.
And then, how do we know that no one else was part of that crowd? In the Gospel according to John, the miracle of the loaves and fishes occurs in Chapter 6, and the writer repeatedly notes the presence of a large crowd following Jesus. In verse 4, the writer also mentions, “Now the Passover, the festival of the Jews, was near,” perhaps as an explanation for why the crowd was so large. Perhaps some of that same crowd were there for Pentecost a few weeks later in the second chapter of Acts. Notice that Luke gives Theophilus a specific list of the wide variety of national origins represented:
“Now there were devout Jews from every nation under heaven living in Jerusalem. And at this sound the crowd gathered and was bewildered, because each one heard them speaking in the native language of each. Amazed and astonished, they asked, “Are not all these who are speaking Galileans? And how is it that we hear, each of us, in our own native language? Parthians, Medes, Elamites, and residents of Mesopotamia, Judea and Cappadocia, Pontus and Asia, Phrygia and Pamphylia, Egypt and the parts of Libya belonging to Cyrene, and visitors from Rome, both Jews and proselytes, Cretans and Arabs—in our own languages we hear them speaking about God’s deeds of power.” ––Acts 2:5-11 (NRSV)
Are you certain that not one of those people were in that crowd when Jesus divided up the loaves and fishes? Not one Arab? Not a single Egyptian? No Roman proselytes? How do you know for sure?
Later in Acts (chapter 8), Luke writes about an Ethiopian eunuch who was traveling from Jerusalem to Gaza. How do we know this didn’t happen previously as well? Could there have been Ethiopians there that day that Jesus fed the hungry crowd?
And what about the possible presence of Samaritans? In the Gospel according to John, Jesus talked with a Samaritan woman at a well as he was passing through Samaria a couple chapters before the feeding of the five thousand. Immediately after their conversation: “Then the woman left her water jar and went back to the city. She said to the people, “Come and see a man who told me everything I have ever done! He cannot be the Messiah, can he?” They left the city and were on their way to him.” (John 4:28-30) In other words, a “city” of Samaritans got on their feet and made a caravan over to follow this Jesus character! Isn’t it possible some of them were still following him when he divided the loaves and fishes? And, are Samaritans “in their own country?” Well, that depends on who you ask. I would guess that given the disciples’ reaction to Jesus talking to her, and given the way Jesus portrays the Samaritan in his parable of the Good Samaritan, most of Jesus’ fellow Galileans would have seen Samaritans as foreigners, or at least not locals.
Did someone check each person’s visa or passport before handing them a loaf or a piece of fish?
And, in any case, if Jesus were here now and saw thousands (millions, if we zoom out) of needy people south of the border, what would he say? If we are the body of Christ, then Jesus is here now, and we have the responsibility to be his hands. We had better act like it.