Unfortunatley there are various gursikhs in the jatha who are anti loud naam abhiyaas. If it is their personal preference to do simran quietly then that's fine. Just don't look down on others. They think they know better and follow lower level gursikhs in jatha (in comparison to bhai sahib) who prefer quiet simran. The point here is that both quiet and loud naam abhiyaas is parvaan in gurmat.
Firstly they are going against Bhai Sahib Randhir Singh who advises to jap naam with force with gurmat vidhi which causes naam russ to come. Secondly let us go direct to the Guru ji for his advice. It is proven in ithaas that Guru Gobind Singh ji gave hukum to Mata ji to do swaas swaas simran and when saying guru touch the tounge to the palate and say guRU with force (zor naal). When done like that, it can give the sound effect of a lion roaring depending on how deep ones voice is. It may sound like a dog barking to his lord master. Or if in even higher pitch may sound like a rainbird singing to the clouds in the sky for the rain drops to come down. So those within or outside jatha who ridicule loud naam abhiyaas who sound like roaring lions are actually laughing at the hukum of Sri Guru Gobind Singh maharaj.
ਮਿਲਿ ਗਾਵਹਿ ਸੰਤ ਜਨਾ ਪ੍ਰਭ ਕਾ ਜੈਕਾਰੋ ਰਾਮ ॥
The sainlty gursikhs do loud jaikare of Akaal!
ਸਤਿਗੁਰਬਚਨਕਮਾਵਣੇਸਚਾਏਹੁਵੀਚਾਰੁ॥
