First of all, until WWI, Morocco was an independent country. Then, it was divided with southern Morocco becoming a French colony and northern Morocco becoming a Spanish colony. During WW II, Spain was neutral. Many thousands of Moroccans from both regions enlisted in the French army based on promises they would become French citizens after the war. They earned that citizenship on the battlefield.
Countries establish their own rules for Olympic eligibility. To be eligible to play for Ireland, for example, you need only one grandparent who is at least 50% Irish.
It is not surprising that many young French citizens play for Morocco. It is easier to make the Moroccan team than the French team. It isn’t unfair that the US had to play a team made up primarily of Moroccans born and raised in France. That is the reality of soccer in the 21st Century. Messi has lived in Spain since he was 13. His entire family had moved there by the time he was 17. He could have played for Spain and perhaps had 3 or 4 World Cup titles by now. Imagine a Spanish team with him at RW instead of Pedro. He could have played in the Euros instead of the Copa America. He chose to play for Argentina and has one World Cup title.
We live in an increasingly mobile world. It’s not like Morocco recruited its soccer players from other countries. All of them are ethnically Moroccan and entitled to compete for Morocco.
They dominated us. Pulisic wouldn’t have made a difference. Three Pulisics wouldn’t have made a difference.