It is stated in Al-Muhannad, the book on belief of the scholars of Deoband page 18, (printed kutub khana Azeezia ‘Deoband,

“Question number 12:

Muhammad Ibne Abdul Wahaab Najdi considered shedding the blood of Muslims, taking away their money and defiling their honor, all these things were lawful.  He also termed everyone else as polytheist and would be disrespectful towards the grandeur of the elders. What is your view about him and about calling the Ahle Qiblah and elders as infidels is it a lawful act? Or do you think that he who does these things belongs to a legitimate sect?