"They are not good leaders."
Translation:Mereka bukan pimpinan yang baik.
For reference to anyone else a bit confused, I understand that pemimpin and pimpinan have different connotations. Pemimpin is a leader in the way western cultures understand leadership, whether by occupation (like a CEO) or having the qualities of. It's used pretty broadly, but generally indicates someone possessing leadership (again, because of a job, or because of their skills/personality/etc.).
I think of pimpinan more as "boss" - it's just someone who has leadership because of their job. In this case, it can also have a negative connotation: They are not good leaders - therefore they don't have good leadership, and shouldn't be called a pemimpin. A pimpinan can have the qualities of a pemimpin, but sometimes a pimpinan is just another boss.
It doesn't help that there's been an effort to reclaim the word pimpinan as leadership, to stop the negative connotations around the government.