يَا أَيُّهَا الَّذِي نُزِّلَ عَلَيْهِ الذِّكْرُ إِنَّكَ لَمَجْنُونٌ
O you upon whom the Reminder has been sent down, you are surely mad.
The verse reports mockery by the deniers. A seemingly descriptive phrase about receiving the Reminder is followed by their insulting accusation, creating a biting ironic effect.
Irony or sarcasm requires a mismatch between apparent wording and the speaker’s derisive intent. The Qur’an reports this false claim; it does not endorse it.