No, the issue was that God had forbidden giving daughters in marriage outside the covenant promise. The blessing to nations was to come via the revelation, not intermarriage. The ancient folks of Shechem were Canaanites; there's good evidence the original name was something other than "Shechem". We have ample precedent for updated place-names in later editions of the Scripture text in other places in the Old Testament. At any rate, the Canaanites were the folks who gave us the worship of Molech, among other abominations. God had already condemned the Canaanites to expulsion or genocide, but the execution of that sentence was to come later. The original inhabitants of what is here called Shechem were under this ban.
Side note: The actions in Genesis 34 resulted in the city being destroyed. At some later date, when Israel moved to Egypt, one of their relatives returned well before the Exodus and rebuilt the place, and his name was honestly Shechem. Thus, during the Conquest, it was an allied city that was spared. However, a Canaanite city nearby was destroyed. We have no idea, and no useful archaeological evidence, of where the two different towns were located, only that both were somewhere near Jacob's Well.
Side note: The actions in Genesis 34 resulted in the city being destroyed. At some later date, when Israel moved to Egypt, one of their relatives returned well before the Exodus and rebuilt the place, and his name was honestly Shechem. Thus, during the Conquest, it was an allied city that was spared. However, a Canaanite city nearby was destroyed. We have no idea, and no useful archaeological evidence, of where the two different towns were located, only that both were somewhere near Jacob's Well.