What is the ruling on not loving some shaykhs?

Loving believers is a great act of devotion (qurbah), and the reward increases with loving scholars, because they are the inheritors of the prophets and the bearers of the Sharia. Thus, they deserve reverence and veneration. Loving believers in general, and scholars in particular, is a sign of faith. There is no harm in preferring to love some scholars over others. However, hating a believer without a legitimate Shari reason, such as open defiance in sin, is a dangerous illness that could lead to disbelief if it is accompanied by mocking knowledge or Da'wah (invitation to Islam).