Why is there so much talk regarding Shaykh Rabīʿ and why do they speak ill about him?

Shaykh Ṣāliḥ ibn Muḥammad al-Lūḥaydān:

He is an excellent man with regards to his religion and his jealousy of the religion. Do you understand?  Do not pay attention to those who speak ill about him, since he refutes the opposers of the religion. The opposer detests him because he refutes those who oppose [the religion]. As for the one who isn’t an opposer [yet speaks ill of him], It could be that he envies him because he [Shaykh Rabīʿ] is aware of that which they are not aware of. He is an excellent man, a man of knowledge and religion.