Imaam Fudayl Ibn Iyaad mentions few stances of a Sunni against a Mubtadi
Imaam Fudayl Ibn Iyaad (d. 187, rahimahullaah) said:
‘If Allaah (the Mighty and Majestic), knows that a man hates a person of innovation, He will forgive him even if his actions are few. A person of Sunnah would not help an innovator except due to hypocrisy. Whoever turns his face away from an innovator, Allaah will fill his heart with faith. Whoever frightens an innovator away, Allaah will grant him safety on the Day of Great Terror and whoever debases an innovator, Allaah will raise him in Paradise by a hundred ranks, so, for Allaah, never shelter an innovator’
Shaikh Saaleh Al-Fawzaan (may Allaah preserve him) said:
Regarding the statement of Fudayl Ibn Iyaad (rahimahullaah): ‘If Allaah (the Mighty and Majestic), knows that a man hates a person of innovation, He will forgive him even if his actions are few: Because this (i.e. having hatred for a person of innovation) is from loving and hating for the (sake of Allaah)- love for the people of Imaan and hatred for the enemies of Allaah. This is a fundamental principle from the fundamental principles of Aqeedah.
[Source: It-haaful Qaaree Bitta’liqaat Alaa Sharhis Sunnah Lil Imaam Barbahaaree (rahimahullaah). Vol 2: page:325-326]