External religious ceremonies lose all meaning when disconnected from moral integrity. A grand display of wealth and effort in worship cannot mask a lack of true dedication to God's ways. The people go to immense lengths to gather rare and precious materials for their offerings. They import frankincense from the distant land of Sheba and acquire fragrant cane, a type of cinnamon used for incense [מצודת ציון]. These luxury items are brought from faraway countries simply because they cannot be found within the Land of Israel [רד״ק].
The primary approach among commentators is that this incense is meant to accompany and elevate the sacrifices. However, because the people's daily behavior is corrupt, the core sacrifices are entirely unwanted. Consequently, God finds no joy in these offerings, making the massive effort to import exotic spices completely pointless [רד״ק, מצודת דוד, ביאור שטיינזלץ]. Taking a different view, [מלבי״ם] explains that importing these spices is not merely a wasted effort, but an actual sin. Having rejected the teachings of the Torah, the people try to invent new religious practices that mimic the customs of foreign nations. Bringing these specific materials from distant lands represents a rebellion. It is an attempt by heretics to cast off their spiritual responsibilities and worship God using foreign, idolatrous methods that He never requested.
The divine rejection is divided into two distinct categories of offerings. The first category is the burnt offering, which is fundamentally designed to appease God and atone for improper thoughts or specific sins. In this case, however, the offerings completely fail to achieve any atonement. The second category involves standard sacrifices, which are not brought for the purpose of appeasement [מלבי ם באור המילות]. Therefore, instead of failing to atone, these sacrifices are simply described as lacking sweetness. Commentators agree that the rejection here means the offerings bring God no pleasure or pleasantness at all [רש״י, מצודת דוד, מצודת ציון].