إِنَّمَا يَتَذَكَّرُ أُولُو الْأَلْبَابِ
Only people of understanding take heed.
On its surface the verse identifies those who genuinely benefit from reminder. In context it can also indirectly reproach people who ignore admonition: their conduct falls short of what understanding requires.
The explicit restriction relates taking heed to people of understanding. The reproach is an implication, not a replacement for that stated meaning.