A Salafi says that the Hadith, "Keep your children from your mosques", is baseless and fabricated.

Answer

Understand well that Salafis are morons. They dwell and flounder in jahl murakkab (compound ignorance), hence they are always prone to disgorge mullock. The Aimmah Mujtahideen and the Fuqaha have cited the Hadith as the basis for deducting a hukm of the Shariah. Hence, regardless of what later Muhadditheen may have classified the narration, the view and ruling of the Fuqaha are of prior and greater importance.

The very utilization of a Hadith as a mustadal (basis of deduction) by a Faqeeh is the evidence for the authenticity of the Hadith notwithstanding the classification of the later Muhadditheen. The Mujtahideen Fuqaha appeared on the horizon of Islam long before the era of the Muhadditheen. The Fuqaha were not reliant on the non-existing later Muhadditheen for the deduction of Masaa-il from the Qur'aan and Hadith and for the systematic formulation of the Shariah. The process of establishing the Ahkaam was effected by the Aimmah Mujtahideen long before the birth of Imaam Bukhaari, Imaam Muslim, etc., etc.

It is therefore only pure stupidity to question the Mustadallaat of the Aimmah Mujtahideen. The acceptance of a Hadith by the Fuqaha-e-Mujtahideen is the best evidence for the authenticity of the Hadith regardless of what the later Muhadditheen may have classified the narration.

The Hadith prohibiting children and mad people from the Musaajid is authentic and the Fuqaha have based the ruling of prohibition on this Hadith. Furthermore, the very Hadith in which children and madmen are mentioned also couples with the prohibition trading, raising of voices, drawing of weapons and meting out punishment. All these acts are forbidden in the Musaajid.